The last guest on the Conan show will be Jack Black. The longest-tenured host in late night officially ended his nightly TBS show Conan on Thursday after a year run. Actor Jack Black; series finale. Actor Jack Black; series finale ComedyMusicTalk-Show. During his final opening. Jack Black: With Conan O'Brien, Andy Richter, Jack Black, Jimmy Vivino. Conan O'Brien closed his TBS talk show "Conan" after 11 years, as "The Simpsons," Will Ferrell and an injured Jack Black helped him say bye. . O'Brien's swan song will air after ten years on TBS and 28 years as a late-night talk. Jack Black took one for Team Coco in the run-up to Thursday's one-hour finale of Conan O'Brien's TBS late-night talk show.