NBC is doubling down on Jimmy Fallon by Benjamin Snyder @FortuneMagazine August 14, 2015, 9:49 AM EDT E-mail Tweet Facebook Linkedin Share icons If you’re a fan of Jimmy Fallon, good news: NBC has signed the comedian on for three and half more years on his popular “Tonight” show. The move extends Fallon’s contract until 2021 and comes just weeks before Stephen Colbert starts his run as the host of “The Late Show” on CBS. Fallon, who took over from Jay Leno, has grabbed the No. 1 rating frequently since he started 18 months ago, according to The New York Times. “It’s nice to say Jimmy’s the guy four weeks before Colbert enters the fray,” Robert Greenblatt, NBC Entertainment’s chairman, told the newspaper in an interview. “We said, ‘Why don’t we just tie him up for a chunk of years?’ ” he added. “He got the job last year, and you give him a three-year deal and see how it goes, and then it’s like, O.K., home run. Let’s lock up the home run.” For more on Fallon, check out his impression of Republican presidential contender Donald Trump on his show recently.