NBC sources say "Saturday Night Live" alumnus Jimmy Fallon will take over for Conan O'Brien when the red-headed comic leaves "Late Night."

The Hollywood Reporter quoted insiders saying the announcement will be made when O'Brien is officially crowned successor to Jay Leno on "The Tonight Show." Both announcements should come within days, the sources said.

The New York Times says Fallon will probably start his new gig in February 2009 when O'Brien leaves for a six-month hiatus before replaces Leno.