TBS said that talks with O'Brien accelerated last week after Lopez called O'Brien to ask him to come aboard.

"I can't think of anything better than doing my show with Conan as my lead-in. It's the beginning of a new era in late-night comedy," Lopez said in a statement released by TBS.

Koonin pitched Lopez on the idea that both he and O'Brien are in their 40s (O'Brien turns 47 on Sunday) and appeal to a young demographic, while Leno and David Letterman are older and play to an older crowd.

"He got very excited," Koonin said. "George saw the vision."

Lopez picked up the phone to speak with O'Brien immediately. With his own show just months old (it began in November), Lopez agreed to have "Lopez Tonight" pushed back an hour.