HBO Max's long-gestating Big Bang Theory spinoff, now titled "Stuart Fails to Save the Universe," has expanded its cast from three leads to four, with John Ross Bowie joining as returning character Barry Kripke. Warner Bros Television originally signed Kevin Sussman, Brian Posehn and Lauren Lapkus in October 2024 as the show's three stars, but Bowie was added four months later, and creators say the change was made to give the comedy a proper antagonist, drawing a deliberate parallel to Lost in Space.

Co-creator Zak Penn said fellow creator Bill Prady pushed for the addition, arguing the show needed a "Dr. Zachary Smith from Lost in Space" — a scheming antagonist figure — and that Bowie's Kripke, the prickly plasma physicist from the original series, fit perfectly. Chuck Lorre praised Bowie as "a brilliant comic actor" joining an already strong ensemble, while Bowie himself admitted he felt briefly disappointed on seeing the initial three-lead announcement before being invited back into what became a reconceived, four-lead version of the show alongside Sussman, Posehn and Lapkus.