CBS's late-night shuffle is happening in 2015, and we now know when Stephen Colbert [1] will officially take David Letterman [2]'s old seat. Late Show With Stephen Colbert will premiere on Tuesday, Sept. 8, at 11:35 p.m. The announcement was made by CBS chairman Nina Tassler, who also announced a handful of renewals [3]. Letterman's final show will be on Wednesday, May 20. In a press release, Colbert hilariously noted, "I have nine months to make a show, just like a baby. So first, I should find out how you make a baby."