You’re a father. What are you doing?

Janice, his wife, sat him down and said: “Listen, I’m going back to work. You’ll take care of Jenny all day. I’ll come home around 5, 5:30, and you’ll go into the clubs in New York and become who I think you can be.”

That gave him courage. When a friend called from a New York University fraternity asking if he knew any stand-ups who would gig for 25 bucks, Crystal pretended to be one. “I lied my ass off,” he recalls. He showed up with barely any material but somehow did an hour. He was a natural, onstage. About eight months later, in January 1976, he performed on Johnny Carson.

“All of this is possible because of that one moment,” Crystal says, some 50 years later, of his wife’s guidance and support. He’s sitting with her in their Tribeca penthouse on a quiet, chilly Saturday in mid-November. On Sunday, he’ll receive the Kennedy Center Honors. “A big deal,” he says, for both of them. Hard to describe.

“When I got the call, I became very emotional about it,” Crystal adds. “My career flashed through my eyes.” He looks warmly at Janice. They’ve been together 53 years now. “Our life together — it’s come to this point.”

He tells this story, and many others, over a tray of store-bought sandwiches and a bowl of plain potato chips. He’s perched in an armchair across from Janice. Their penthouse is decorated with treasured paintings, including two by his buddy’s dad: Robert De Niro Sr.

In a nearby screening room, a photograph of the 1937 Oscars ceremony at the Biltmore Hotel hangs over the couch. It was taken 53 years before Crystal first hosted the show. He excitedly points out Spencer Tracy and Spike Jones in the photo.

Crystal, now 75, is a true believer in showbiz, a sultan of sentimentality, a Zelig who somehow managed to know nearly every significant cultural figure of the past half-century. Mickey Mantle confided in him, and Joe DiMaggio once punched him in the stomach. He took fashion advice from Alan King and comedy advice from Jack Rollins. Martin Scorsese taught him film directing at NYU. He wandered onto sitcom sets for surprise cameos with Robin Williams.

Muhammad Ali dubbed him “little brother.” George W. Bush called him “Billy C.” To Billie Holiday, he was “Mr. Billy.”

He never had a specific plan, he says, but “I knew I didn’t want to be one thing.” So he hasn’t been. He’s been an author, a stand-up, a Broadway star, a movie star, a TV star. A director, a host, an improviser, an impressionist. A master of both the one-liner and the double take. Screenwriter Eric Roth calls him a “variety show” in human form.

Crystal became a bridge between old and new Hollywood, between the Borscht Belt and the Sun Belt and the Rust Belt. He applied the hidebound traditions of vaudeville in the frenetic era of mass media. He was a Bob Hope for modern times.

Whenever or wherever he showed up, you laughed. You felt good.

As Crystal sums it up: “I entertained.”

Some one-liners from friends:

• “He’s my uncle, he’s my godfather, he’s my everything.” — “Here Today” co-star Tiffany Haddish, who honored him with a prayer at her adult bat mitzvah.
• “He’s a lesson in being true to yourself.” — Alan Zweibel, frequent co-writer and lifelong friend.
• “He’s unspoiled.” — Des McAnuff, director of “700 Sundays.”

He was born into a showbiz orbit. His grandfather owned the Commodore Music Shop, a record store on East 42nd Street that his father Jack managed. His uncle produced Nat King Cole and Bing Crosby for Decca Records. When he was around 5 years old, Billie Holliday took him to his first movie; she had some time to kill between sound check and a concert his father was producing. Crystal watched the Yankees from Louis Armstrong’s box. His family doctor was Don Rickles’s cousin.

During his childhood in Long Beach, N.Y., Crystal idolized Sid Caesar and Mantle in equal measure. He’d later write: “All I really wanted to be was a Yankee. A Yankee who was also a comedian.”

Crystal graduated from NYU in 1970, a year before classmates Oliver Stone and Christopher Guest. In 1976 — after struggling as a substitute teacher in a middling comedy trio, after late-night drives to comedy clubs while the baby slept, after asking What am I doing? over and over again — his uncanny Muhammad Ali impersonation earned him a spot at Dean Martin’s roast of the boxer.

Then came Carson. Then came “The Hollywood Squares” and “The $20,000 Pyramid” and “The Love Boat.”

On TV, he started becoming what Janice thought he could be.

Norman Lear “brought me to the dance,” Crystal says, after seeing his set at the Comedy Store in Hollywood and casting him in an episode of “All in the Family” as Rob Reiner’s best friend.

“Rob and I said, ‘This is good. Why don’t we continue this in real life?’” Crystal says of their dynamic. “That led to our relationship as inseparable friends, which led to three movies that are a big part of why I’m getting this award.”

“This Is Spinal Tap” and “The Princess Bride” proved Crystal could be memorable in brief roles, while “When Harry Met Sally …” cemented him as a charismatic leading man, deft at both comedy and drama. Castle Rock Entertainment, the company Reiner co-founded, would produce several Crystal vehicles, including “City Slickers.”

He played TV’s first unambiguously gay character on the sitcom “Soap” from 1977 until 1981. He briefly hosted his own variety show. He made his Broadway debut at 56 and his Broadway musical debut at 74.

And he befriended just about everyone along the way.

“A lot of people in comedy don’t laugh at other people,” says Martin Short, Crystal’s co-star for the 1984-1985 season of “Saturday Night Live.” “Billy laughs hysterically at anyone he finds funny.”

His 1985 stand-up album “Mahvelous!” had the energy of a variety show. The TV fundraising series “Comic Relief,” with Robin Williams and Whoopi Goldberg, raised $75 million to buy medical supplies for the homeless. In 1999, “Analyze This” put Crystal opposite Robert De Niro and lit up the box office.

And, of course, he became the quintessential Oscars host. As a child, he would gather around the black-and-white TV with his family to watch Hope or Carson emcee the night — “a special one-night pass to sit in the palace with the legends,” Crystal would later write. He followed Hope and Carson into the hosting role in 1990.

Over a span of 22 years, he hosted nine times, second only to Hope, turning perhaps the hardest job in Hollywood into his hallmark. Crystal made the ceremony into both blockbuster and supper club — a spectacle that felt intimate. It became must-watch TV and earned him four Emmys.

“He changed the whole approach to it,” says Jimmy Kimmel, who next year will host the Academy Awards for the fourth time. “He gave me the most valuable advice on hosting the show: You have to play to the room, not to the people watching at home.”

Crystal has always mined his own life for inspiration. Much of the central relationship in “When Harry Met Sally …” — perhaps his most enduring film — mirrors Crystal and Reiner’s (minus, well, the orgasms, faked or otherwise). He based the dementia-stricken writer he portrayed in “Here Today” partly on SNL writer Herb Sargent and partly on his aunt, a novelist who once told him “I’m losing my words.” Crystal was a Jewish comic who got the performing bug by entertaining his family members in his living room, so he wrote and directed “Mr. Saturday Night,” a movie about a Jewish comic who gets the performing bug by entertaining his family members in his living room.

Crystal spent the past two decades on personal anthropology, excavating details of his life for his one-man, Tony-winning Broadway show “700 Sundays” and his autobiography “Still Foolin’ ’Em.”

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That’s the funny thing about the showman: “He’s not really putting on a show,” friend and writer Alan Zweibel says. He’s just being himself.

“He’s such a good storyteller,” Kimmel says. “That’s probably at the heart of everything he does: He’s able to tell stories from his life so well.”

Stories, anecdotes, memories — telling them is how Crystal connects with the audience, even an audience of one.

When I mention that, as a high-schooler, I once bagged groceries for his “Monsters, Inc.” co-star John Goodman, it sends the Crystals into a duet of reminiscence.

“I knew I didn’t want to be one thing.”

— Billy Crystal

“You had a similar experience back in Long Beach,” Janice tells Billy. “Was it Cab Calloway?”

“Oh God,” Crystal says, and suddenly he’s a paperboy again, passing a stack of newspapers into Calloway’s sleek Pontiac convertible every morning at 7. The bandleader, tuxedo shirt unbuttoned at the neck, would hand him a ten and tell him to “keep the change.”

He ran into Calloway years later at “Night of 100 Stars” while wearing the makeup of his suave, smarmy character Fernando from SNL. Crystal told him that he was the “newspaper kid” who would hand him the papers when he drove up in his Pontiac. Rather than react to seeing this kid all these years later, at the epicenter of the entertainment world, Calloway goes: “Yeah, that was a great car.”

Janice laughs. “I love that story,” she says.

Crystal’s philosophy is neatly summed up in “Here Today.” His character greets his dementia diagnosis with wisecracks. “This is no time for jokes,” the doctor says. “Yes it is,” Crystal says, leaping to his feet. “It’s the perfect time for jokes, goddammit. Don’t try to take away my sense of humor. I’d rather die right now.”

Crystal says humor is essential, “especially now with so much disinformation, so many avenues for poison to get into people’s minds, so much small thinking. Any insight that can be shrouded in comedy can make a point better than someone pointing a finger.”

Which is partly why, in 1989, he jumped when Michael J. Fuchs, then head of HBO, asked him to be the first American comedian to film a special in Moscow. Who better to begin soothing relations between the cold-warring countries than the consummate entertainer?

“This is a bit of history,” Fuchs said at the time of the special, “Midnight Train to Moscow,” which cost seven figures to produce. “The voice of comedy is as socially relevant as any voice, and Billy is not your typical comedian. He’s capable of presenting a point of view with intelligence and relevance.”

In preparation, Crystal walked the streets of Moscow with a KGB officer, keenly aware they were being watched. He met with the U.S. ambassador, who wouldn’t let him talk until they reached a certain room of the house because it was bugged. He shot handheld video on the street.

“Even to this day,” Crystal says, “I think, ‘Man, I had balls.’”

If comedy is his philosophy, then baseball is his religion. The game works its way into most of his art. Crystal learned to throw curveballs on the fields of Long Island High and went to countless Yankees games with his father, who died when Crystal was 15. He went to his first college on a baseball scholarship. In “Midnight Train to Moscow,” which begins with a visual riff on “Field of Dreams,” he swaps baseball tips with Russian players.

He plays an avowed Cubs fan in “Running Scared” and a baseball announcer in “Parental Guidance.” And he directed “61*,” the HBO film about Mantle and Roger Maris’s quest to break Babe Ruth’s home run record.

When describing him, both Reiner and Kimmel use a variation of the baseball term “five-tool player.” Crystal even has a World Series ring as a part owner of the Arizona Diamondbacks.

Crystal occasionally worked out with the Yankees. “I was like the 26th man,” he says. But he wanted more. Ahead of his 60th birthday, he asked Derek Jeter to help him fulfill a lifelong dream.

March 13, 2008, was “the real highlight” of his career. After signing with the team during spring training, after practicing intensely with Reggie Smith, after donning the number 60, he spent one at-bat as a pro — making solid contact with a pitch, sending it just this far outside the first base line, then striking out. He retired right after.

“I’ve walked onstage where a billion people see you at the Oscars,” Crystal says. “It’s thrilling to look out and there’s Streep and Coppola and Jack, of course, and all of the greats. I’ll never forget all those moments I was able to have onstage. But I can always say I was a Yankee. And that somehow means everything.”

Some more one-liners from friends:

• “The triumph for Billy is he’s a spectacular husband and father and grandfather.” — Martin Short
• “In spite of the fact that he’s a titanic celebrity, he’s a real family man.” —Des McAnuff
• “Cut him open, and his family’s inside: That’s his essence.” — Alan Zweibel

In one’s 70s, What are you doing? starts turning into What have you done?

Turns out: Everything. It’s easier to talk about Crystal’s career in terms of what he hasn’t done.

“He’s never done any tailoring,” Reiner says. “It’s one area for his body of work that’s really lacking.”

Crystal has never been a full-time host for a late-night show like Carson’s, though Fox offered him one in 2007. He would’ve been perfect for the job — but didn’t want to spend that much time away from his family: Janice, their two daughters and four grandchildren.

“I’ve walked onstage where a billion people see you at the Oscars. It’s thrilling to look out and there’s Streep and Coppola and Jack, of course, and all of the greats. I’ll never forget all those moments I was able to have onstage. But I can always say I was a Yankee. And that somehow means everything.”

— Billy Crystal

And that’s what it comes down to, for Crystal. For the man who’s done everything, who knows everybody, he always returns to his first love, his first audience: family. He laments losing his father so early in life. His wife and children’s sacrifices — that’s why he’s now a Kennedy Center honoree.

“I wanted them to know how happy I was doing what I was doing,” he says of his two daughters. “That I had to do that. That it was my goal in life. I was achieving what I always wanted to do.”

It was a lesson he worked to instill in them: Be happy in what you do. His eldest daughter, Jennifer, is now an actress. Lindsay is a producer and director.

For all the pomp of the Kennedy Center Honors weekend — which includes a trip to the White House and dinner at the State Department — he and Janice are most looking forward to having the family with them. The event, the honor, the singular career of Billy Crystal — they talk about it all in terms of “we.”

“When we met, we were so young,” Janice says. “Who thought we’d be here? We still feel like kids on Long Island.”

The Kennedy Center Honors will be broadcast Dec. 27 at 9 p.m. on CBS and stream on Paramount Plus.