Jimmy Fallon by Chris Haston/NBC Universal Photo

This fall - some six months before his Late Night talker hits the airwaves - Jimmy Fallon will attempt a "soft launch" of the show, performing five- to 10-minute routines on an NBC online portal TBA. This unorthodox "dry run" is intended to let Fallon find his voice and rhythm and thus avoid the sort of pitfalls that plagued Conan O'Brien when he himself entered the late-night realm.

As for Conan, he is expected to cease production on his Late Night in February, then head west to prepare his take on The Tonight Show, which will premiere sometime in June - and from a brand-new stage now in production.

Fallon's Late Night is slated to hit NBC proper "sometime in the spring," giving him Leno as a lead-in for a brief stretch. - Matt Mitovich