David Letterman is preparing to retire from late-night television later this year after working for over 30 years in the industry, and questions about his replacement dominated CBS’ TV press tour in Pasadena on Monday morning. CBS Entertainment chairman Nina Tassler told reporters that Late Show With Stephen Colbert will bring new life to the competitive late-night format, and is scheduled to premiere on Sept. 8.

Viewers will have a difficult time knowing what to expect from Stephen Colbert when he takes over Late Show duties from Letterman, since most know Colbert for his satirical self-absorbed, right-wing persona on Comedy Central’s Colbert Report. Tassler promised that audiences will finally get to know “the real Stephen Colbert” in September, since the network is “letting him do what he wants to do” on the show. For example, even though opening monologues have been a late-night tradition since NBC’s Tonight Starring Steve Allen in the mid-1950s, CBS told Colbert he’s free to start the show without one if he so chooses.

“He’s working on that now,” said Tassler. “There will be parts that will be traditional in some contexts and there will be things he wants to do differently. He’s a real student of media. He knows the format better than anybody.”

Colbert’s late-night show will feature music and guests, but Tassler said that they may be incorporated into the program in unusual ways. However, she assured reporters that while the show may be unconventional at times, it will always be topical, relevant, and deal with current events.

Until Colbert’s debut, CBS will be focused on turning 36-year-old British actor and TV host James Corden into a fitting replacement for Craig Ferguson on his 12:35 a.m. Late Late Show by March. Tassler called Corden “a combination of Jack Black and Fred Astaire,” and said that she and CBS chief Leslie Moonves were mesmerized when they interviewed Corden for the job. Until he’s ready, the network will be hiring several guest hosts to fill in for the position.

While CBS’ late-night shows are going to change drastically this year, viewers can expect much of the same from their prime-time lineup. Tassler announced that the network ordered second seasons of freshman dramas Madam Secretary, NCIS: New Orleans and Scorpion. New crime thriller Stalker wasn’t as lucky, but Tassler said it may still be reordered.