The longest-tenured host in late night officially ended his nightly TBS show Conan on Thursday after a year run. Jack Black: With Conan O'Brien, Andy Richter, Jack Black, Jimmy Vivino. The last guest on the Conan show will be Jack Black. . 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. Actor Jack Black; series finale ComedyMusicTalk-Show. O'Brien's swan song will air after ten years on TBS and 28 years as a late-night talk. During his final opening. Actor Jack Black; series finale. 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.