Jimmy Fallon by Jason Kempin/WireImage.com Jimmy Fallon by Jason Kempin/WireImage.com

Confirming the worst-kept secret in television, NBC today officially introduced comedian Jimmy Fallon as the network's newest late-night host.

The SNL alum will start as host of Late Night (Weeknights, 12:30 am/ET) when Conan O'Brien takes over the Tonight Show for Jay Leno in 2009.

Ironically, O'Brien's show was the first talk show Fallon appeared on after joining SNL in 1998.

Fallon, 33, told a news conference he has been destined to host a late-night talkfest since he was a kid. "In my kindergarten yearbook, they wrote 'Most Likely To Take Over For David Letterman,'" he said.

Exactly when Fallon will make his debut next year is still up in the air, and appears to be hinged on where Jay Leno lands after the Tonight Show. "Everyone wants Jay Leno to stay part of the NBC family," said SNL boss Lorne Michaels, who will also executive produce Fallon's show. "And that's a big part of what's going on now."

Fallon joked once he starts, he's in it for the long haul. "NBC gave me the same contract as Willard Scott - 150 years." - J.R. Whalen