As is often seen in the movies and on TV, just about anyone is bound to pop up on a New York City subway: MC Lyte, Jason Voorhees, Spider-Man, Doc Ock and now Usher.

In his new video for "My Boo," Usher is missing Alicia Keys so much he leaves his hotel during the middle of the night and takes the train to clear his head (something he actually did in real life not too long ago). Once he's above ground again, he sings and walks, almost getting taken out by a taxi (join the club, Ush) before finally meeting up with his former onscreen romantic partner. As it turns out, Keys, who logs plenty of video time in a sexy nightgown, has the type of listlessness a late-night room-service snack won't cure.

"The video is gonna be crazy," Keys said last month in Miami, where she was on hand for the Video Music Awards. "It really stays in form in what the song is talking about. The song is talking about the first person you ever really had feelings for. I think we all know what that feels like. Even though you move on and meet new people, you always remember that first person."

Around the same time when most teens' biggest problem is dealing with the joy and pain of puppy love, Usher and Alicia Keys were beginning their singing careers. The two crossed paths and became friends.

"We've known each other for a really long time, probably before his first album popped off," Keys said. "We were both about 15. We've always kept in touch -- said, 'What's up?' and that kind of thing. But it wasn't until this year that it came together the right way."

Besides "My Boo," the two also teamed up on the remix of Keys' "If I Ain't Got You" (see [article id="1490153"]"Usher Returns Favor By Appearing On Alicia's Revised Diary"[/article]).

Like Usher, Keys is looking to release another variation of her current album.

"What we're really looking into is doing an 'Unplugged' kind of version for a live album," she explained. "For me, performing is the epitome. I love songwriting, I love getting into the studio, but it's when you get on that stage, for me, it really translates to the people just how passionate I am about the words that I write. That's the next thing that we're working on. It should be just a gem. It will be like a live show."

There is no official word yet on whether the live album will definitely happen or when it would come out.