My answer is always the same -- Paul McCartney.
I've met a lot of celebrities in my life and been in a lot of rooms where journalists have fired questions at famous people -- everyone from Fred Astaire, Paul Newman, Robert Redford, Lauren Bacall and Jane Fonda to Billy Crystal, Robin Williams, Whoopi Goldberg and Jerry Lee Lewis.
I never waffle. If you ask me who is the most charming celebrity I've ever met, Paul McCartney is always the answer. He always will be, too. Yes, Joe Namath was a huge and pleasant surprise. Yes, Tom Hanks could charm the feathers off a shivering peacock.
But there's no one like Paul McCartney. I've never met anyone afflicted with an equally toxic level of fame who has handled it with more level-headed aplomb and human sympathy than Paul McCartney.
Millions have been discovering why afresh since last week ushered in McCartney's 76th birthday and James Corden's latest -- and arguably greatest -- bit of Carpool Karaoke, in which he and McCartney drive around Liverpool taking in the sights, i.e. places whose mere existence has become famous just because the Beatles began there.
Corden has been doing much-loved Carpool Karaoke with everyone from Christine Aguilera to Justin Bieber, Madonna and Miley Cyrus, but Corden and McCartney are as charming as any 23 minutes and 42 seconds of TV you're liable to see anywhere.
They stop at "Penny Lane" to sing the song and allow Paul to join the many tourist signatures on the street sign. They amble over to the local barbershop (mentioned in the song).
They sight-see in the flat where Paul spent his youth writing songs with John Lennon. That means, yes, Paul steps into the loo to sing "She Loves You, Yeah, Yeah, Yeah" and clap and show off its resonant acoustics.
McCartney then goes over to the house's piano, bangs out some accompaniment and sings "When I'm 64" with Corden. (At 76, his singing voice occasionally has a faint hint of age's quaver, but he looks great.)
Then he confesses to Corden that his dad -- a musician, too, as Beatles fans know -- asked him and John, "Couldn't you sing, 'She Loves You, Yes, Yes, Yes?' There's enough of these Americanisms around."
All the time Corden and McCartney sing McCartney songs together, Corden is -- surreptitiously -- doing one of the most affecting interviews with Paul that has ever been done on television.
When McCartney tells the story of dreaming of his mother telling him, "Let It Be, Let It Be" they sing the song together and both choke up a little. Corden's grandfather introduced him to the song when he was a child by telling young Corden it was the most beautiful song he'd ever heard. So while Paul remembered his mother, a tearful Corden remembered his grandfather.
Then to lighten up with some real native Liverpudlian fun, they stop at a pub where the Beatles performed back in the day -- a place now called The Philharmonic Dining Room. The two perform impromptu for that afternoon's ordinary publicans assembled for some food and talk and a pint or two. McCartney then disappears and reappears on the joint's stage playing his left-handed guitar and leading a couple of musical mates. It's an improvised mini-concert.
" A Hard Day's Night" begins the set. Then, "Oobla-Di-Oobla-Da." Word has gotten out. The place quickly fills up. "Back in the USSR" comes next. McCartney is sweating through his blue oxford shirt -- just as he might have a half century before.
The finale is "Hey Jude." "Let the People Sing" shouts Paul and the whole room joins in. Many are crying. These are anthems that, for some of them, could conceivably go back four generations already.
It is Paul McCartney's singular charm that you are unlikely to find anyone on earth who is more joyously and plainly himself under all the celebrity circumstances. He has spent more than a half-century as one of the most loved and recognized human beings on earth and he knows how to be himself and enjoy it no matter what. He's had as much training doing it as anyone.
He knows everything people love about him. He knows everything they're not so sure about, too. What endears him to journalists is that hard questions -- sometimes very hard -- don't really phase him. When Lennon -- one half of the Beatles' heartbeat -- sneered in a song "How Do You Sleep?" Paul simply admitted that their relationship, like all relationships, had its ups and downs. I've never known a journalist to get really down and dirty and talk money with him in ugly ways, but I have no doubt that he'd bring equanimity and human sympathy to that, too.
You have to remember that when some millennial music nightclub on the coast, refused entry to McCartney and friends at the door because he didn't fit in with the current demographics of the clientele, he joked, "I guess we'll have to sell a few more records." (He has a new one out now called "Egyptian Station.")
Corden and McCartney leave the Liverpool club where there's been that impromptu mini-concert. They wade through a large street crowd of sudden McCartney admirers.
A man among them shouts out, "Your music was played at my dad's funeral!"
Believe me, Paul McCartney knows that. He didn't know the guy or his dad personally, but he knows how close his music has been to people since 1962.
He's proud of it, yes, but he's genuinely human enough to be humbled by that intimacy, too.
Watch him show James Corden the sights in Liverpool and you'll more than sense it.