NBC had committed to giving him the "Tonight" slot five years ago, although it was only recently that current host Jay Leno decided to stay with the network and do a nightly 10 p.m. show.

Most of O'Brien's writers will head to California with him. Years ago, switching to that earlier time slot might have meant dramatically changing the tone of the show to appeal to an older audience. But the late-night habits of viewers are different now — many watch the next day on digital video recorders — and the need for such changes has lessened.

"The shows are an extension of the host and, like it or not, this is my sense of humor," O'Brien says. "It would be a mistake to reinvent myself as a completely different person now."

His biggest danger moving to Los Angeles, outside of sunburn, is overthinking things. And O'Brien will be facing more formidable competition with Letterman. Although O'Brien generally maintained the top ratings position in his time slot, CBS' Craig Ferguson has been catching up.

After Leno's surprise announcement that he's staying with NBC, there was immediate speculation that it might be bad for O'Brien, that he'd lose out on booking wars and still be seen as a second banana to Leno.

But O'Brien said one night on "Late Night" that he was looking forward to the new schedule.

"You can talk to me in a year and I'll say 'Well, there are some problems, there are some complications,'" he said. "But I don't know what they are. I don't know if there will be."

Even as it became clearer that Leno wasn't eager to leave, O'Brien didn't waver in wanting to keep to the original deal. He never got a sense that NBC wanted to change, either.

O'Brien is trying to maintain the element of surprise for his last week of shows, saying he wants to rely on old friends of "Late Night" instead of stunt casting. Don't be surprised if Andy Richter, O'Brien's on-air sidekick until he left in 2000, stops by. Same with Al Roker who, because he works in the same building, has been the show's most frequent guest.

"The one thing that's worked consistently for me is just to use your common sense, just try to be funny," O'Brien says. "For 16 years, I've just been trying to think of funny stuff. We miss sometimes, we hit sometimes but I think our average is pretty good."

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On the Net:

http://www.nbc.com/Late_Night_with_Conan_O'Brien/

Copyright 2009 The Associated Press.