Celebrity Sightings at New York Fashion Week

Paul McCartney gets into a dance-off with Kendall Jenner, freaks out fans on the elevator and writes a hate song about "creepy" Jimmy Fallon.

Paul McCartney was clearly having a lot of fun during his Thursday night appearance on "The Tonight Show," even if Jimmy Fallon's fanboying did start to creep him out a little bit.

Paul definitely seemed to enjoy dancing with fellow guest Kendall Jenner and freaking out fans in the elevator, and there was a twinkle in his eye as he called out fellow artists Beyonce and Taylor Swift, blaming them for why he can't put out pop albums anymore. And then there was Jimmy.

There's fanboying over your guest -- which is kind of a Jimmy Fallon signature move -- and then there's bringing in all your Paul McCartney memorabilia from your childhood bedroom and putting on a gushing show-and-tell in front of your musical idol. Guess which direction Jimmy went?

Honestly, the whole segment was so earnest and Fallon so sincere that there was a sweetness underneath the growing creepiness of it. But at least Jimmy was able to read the room. After showing Paul some of his favorite albums, including indentations where he had clearly traced Paul's head one one of them, he said, "Stop me when it's getting creepy."

"No it's fine, Jim. I'm loving this," Paul joked right back.

"Hello, This Is Paul McCartney"

The two shared an easy rapport throughout the night, and you couldn't help but laugh and smile right along with them. And Paul did find it genuinely sweet when Jimmy revealed the indentations of an actual fan letter he had written to his idol when he was 10 years old.

He had clearly put the paper on the album jacket, making the letter still readable by indentation. "My name is Jimmy. You're my favorite singer in the world. I'm 10-years old," Jimmy read. "And I put my phone number."

And then they decided just for giggles to call the number and see if anyone answered. Jimmy didn't even know who might have the number now, and then no one picked up. But at least Paul was able to leave a message that is going to both delight and confuse the owner of the number.

"Hello, this is Paul McCartney," he said. "I'm looking for Jimmy Fallon. If you see him, can you have him call me back. Thank you."

"They've Got Better Legs"

One of the things about Paul's latest album, "Egypt Station," that Jimmy noticed was that it seemed to flow more like a concept album than the types of albums The Beatles and Paul himself traditionally has done through his career.

"We figured we can't really do the modern pop album where it's just like a bunch of singles," Paul explained. "People like Taylor Swift and Beyonce have got that kind of thing covered and they've got better legs than me." With a wink to the audience, he added, "Just."

The legendary performer also teased his "surprise" concert scheduled for Friday night, but it's not such a secret anymore. "The album's title is "Egypt Station." There might be a little clue there," he said. "It might be a Grand show, I don't know."

Jimmy was totally confident he'd cracked the code. "We'll see you tomorrow night at the Statue of Liberty!" he trumpeted.

"I Really Hate Him"

Paul explained that for him, a lot of times he uses the art of crafting a song to process through negative emotions. Most of his music is positive and uplifting, and he attributes that to the songwriting experience being able to lift his spirits. But often it comes from a darker place.

"Are you in a good mood tonight?" Jimmy asked him.

"No," he responded. For Jimmy, this just meant it was the perfect time to get those creative juices flowing. As Paul glowered at the audience (which was really just adorable if we're being completely honest), Jimmy decided to hit him where it hurts.

"I'm just saying, I think Ringo was the shy one and the cute one," he said smugly. "I'm saying I have proof that he was the walrus."

That was all it took, and Paul broke out into song. "I used to like this guy, but now I hate him / I really hate him, I hate him, I hate him," he sang. "I really hate this little sucker, he's a mean--" But Jimmy had to shut him down right there. Maybe it's not a great idea to get a former Beatle mad at you. There's power in music!

"I Thought I Was Gonna Marry Paul McCartney"

The power of the music of Paul McCartney has touched so many lives around the world that he is an instant icon and just seeing him in the flesh is enough to reduce us mortal folks to tears. That's what happened to several random people who thought they were getting a tour of 30 Rock.

Instead, when the elevator doors opened, they were treated to several random vignettes featuring Jimmy and Paul. At one point, they were both sitting in their evening jackets in side by side recliners reading the newspaper. When the doors would open, Jimmy would peer over his paper first, to the delight of the crowded elevator. But when Paul's paper dropped, they started to scream.

"When I was little I thought I was gonna marry Paul McCartney. That's the closest I have ever got, and I am thrilled," said one woman later, with tears still in their eyes.

At other points, they could be seen playing ping-pong (badly), performing a magic trick or even simply chatting. But every time, the genuine reactions from the excited guests on the elevators made it all worthwhile. What a memorable and bizarre experience they can share.

Song and Dance Man

In the spirit of randomness, the show even opened with Kendall Jenner simply dancing away in her dressing room to the music of Paul McCartney. Within minutes, Jimmy and finally Paul had joined her, just wordlessly enjoying the moment. By the close of the show, though, it was everyone else in the studio who was able to dance while Paul performed his track, "Come Onto Me," which you can check out below.

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