In a marathon session, lawyers for the talk show host and NBC finalized a settlement sealing O'Brien's exit from "The Tonight Show" at about 3 a.m. Thursday. The overall deal is said to be worth $46 million-$47 million, close to the $50 million annual production cost of "The Tonight Show With Conan O'Brien."

O'Brien's settlement is for about $33 million, with the rest of the money going to his staff in severance packages from the network. NBC on Thursday also formally announced the return of Jay Leno as "Tonight" host. He'll start March 1. "We're pleased that Jay is returning to host the franchise that he helmed brilliantly and successfully for many years," said Jeff Gaspin, chairman of NBC Uni TV. "He is an enormous talent, a consummate professional and one of the hardest-working performers on television."