Fallon Stepping Into Letterman and O'Brien's Shoes Next Year

The announcement, which had been expected for weeks, was made during a press event from NBC headquarters in New York atop 30 Rockefeller Center, where O'Brien's "Late Night" show is taped.

Fallon, a former cast member on the network's "Saturday Night Live,'' will take over as host of the 12:35 a.m. show in mid-2009, while O'Brien will move next year to the "Tonight Show,'' replacing Jay Leno.

Leno, 58, had announced in 2004 that he would retire in 2009.

"It's going to be a grind, it's going to be hard, but I'm going to go at it full force," Fallon told reporters on a conference call.

"The fact that I'm stepping into David Letterman and Conan O'Brien's shoes is very exciting."

Fallon, 33, joined Saturday Night Live in 1998. He remained a cast member for six seasons, where he co-anchored the "Weekend Update" news segment with 3rd Rock's Tina Fey.

He left the program to focus on making feature films, although such efforts as Fever Pitch,

Taxi as well as voice work on the animated films Doogal and Arthur and the Invisibles.

Though the network declined report an exact start date for Late Night with Jimmy Fallon, it is expected to debut in mid-2009 after a renovation of the Rockefeller Center studio where O'Brien now films his show.

General Electric Co., which owns NBC Universal, closed 15 cents or 0.4 percent higher at $32.40.