3-year theory: Big renewal deal for 'Big Bang'

3-year theory: Big renewal deal for 'Big Bang'
This undated photo released by CBS shows, from left, Johnny Galecki, Kaley Cuoco, Mayim Bialik, Jim Parsons, Melissa Rauch and Simon Helberg of The Big Bang Theory. (AP Photo/CBS, Monty Brinton)
NEW YORK (AP) - CBS says it's renewing its hit comedy "The Big Bang Theory" for three more years.

The extraordinary three-year deal would carry TV's most-watched sitcom through the 2016-2017 season, the series' 10th on the air.

"The Big Bang Theory" premiered in September 2007 and has been a ratings smash for virtually its entire run. It has averaged nearly 20 million viewers each week this season.

A comedy about science nerds and the people who love them, it stars three-time Emmy-winner Jim Parsons as well as Johnny Galecki and Kaley Cuoco-Sweeting.

It airs Thursday at 8 p.m. Eastern time.