Conan O'Brien Sets End Date for TBS Show Rich Polk/Getty Images for Xandr The host will bring his nightly show to a close in late June but will continue his relationship with WarnerMedia via a weekly HBO Max series. The longest tenured host in late night has set an exit date. Conan O'Brien will end his nightly TBS show on June 24, the cabler announced Monday night. It will bring to an end the host's 28-year run as a late night host, stretching back to 1993 when he took over NBC's Late Show from David Letterman. TBS' parent company, WarnerMedia, said in November 2020 that