When the fourth season of Hacks premieres this week, newly minted late-night talk show host Deborah Vance (Jean Smart) is going to run into two real-life TV superstars. Entertainment Weekly reports that Carol Burnett and Jimmy Kimmel will guest-star as themselves on the upcoming season of the hit HBO comedy. While Burnett will turn up to lend support to Vance, Kimmel's role on the series will be more adversarial.

Hacks' fourth season will center around comedy legend Vance finally getting her shot to headline a late-night talk show, with her on-and-off frenemy Ava Daniels (Hannah Einbinder) making herself its head writer via blackmail. In the season;s fourth episode, the pressure soon gets to Deborah, as she experiences her first-ever case of stage fright while in rehearsals for her first episode; she finds some support in the form of comedy veteran Burnett. As Smart says, Deborah wouldn't admit her vulnerability...