Will Ferrell will likely be the first official guest when Conan O'Brien takes over the "Tonight Show" Monday, June 1, it was announced today. Ferrell briefly appeared on O'Brien's "Late Night" finale in New York in February, and will now help O'Brien kick off his tenure on "Tonight" in Los Angeles.

Pearl Jam will be the first band on O'Brien's show, playing songs from an upcoming studio album, NBC said Monday.