Billy Joel's 'Last Play at Shea' plays Citi Field

Since documentaries don't usually debut in baseball stadiums, no one is exactly sure what will happen when Billy Joel's "Last Play at Shea" premieres at Citi Field on Saturday night. Not even Billy Joel.

"I was calling my agent asking, 'Do people know what they're buying?' " Joel says. "I hope people don't think I'm going to be doing a show."

The uncertainty, of course, does make the event more exciting for Joel, who will be in attendance for the documentary, which weaves together the stories of Shea Stadium, the New York Mets and Joel's career. "I'm kinda looking forward to seeing what happens like everyone else."

WHAT TO EXPECT 

• "Maybe it will be like a big drive-in, except you won't be in your car," says Joel. "Maybe that's the feeling to expect."

• "It's really a Mets-oriented movie," he says. "They're in it as much as me."

The still-amazing story of how Paul McCartney went from being on a commercial flight from England bound for Kennedy Airport to the stage at Shea Stadium in under an hour. "It really was a game of 'Beat the Clock,' " says Joel, adding that the story of McCartney's tuning his bass backstage with a butter knife was true. "We were in shock when he made it."

WHAT NOT TO EXPECT

• "It's not a straight-ahead concert film," says Joel, adding that he's "bored to death of concert films. . . . I don't think we do a complete song in the movie." 

• Lots of early footage and photos of young Billy Joel. "There was a fire in my mom's house and all the photos of me from age 5 to about 20 were burnt up in the fire," he says. "All the boxing photos and me in my early bands were lost." 

• "I won't be making a big speech or anything," Joel says. "I hope people aren't expecting Lou Gehrig to walk out and say, 'Today, I am the luckiest man on the earth.' I'm not going to do that." 

WHO "Last Play at Shea"

WHEN | WHERE 8 p.m. Saturday, Citi Field, Roosevelt Avenue, Flushing

INFO $10; 718-507-8499, 507TIXX.com