The spin-off ofThe Big Bang Theory,Stuart Fails to Save the Universe, brings back an actor who has played a significant role in most of Chuck Lorre’s shows. In March 2025, it was announced thatThe Big Bang Theorywould be getting a spin-off calledStuart Fails to Save the Universe.

The show follows the fan-favorite character, Stuart, as he navigates through the multiverse in an attempt to save the world and restore reality to its former state. Combining situational comedy with science fiction, the new spin-off takes the absurdity of the original show to a whole other level.

Stuart & Sheldon making faces as they stare at each other in The Big Bang Theory

Several cast members are reprising their roles inStuart Fails to Save the Universe. Director Chuck Lorre is returning as the creator, andKevin Sussman is returning as Stuart Bloom. Other characters include Lauren Lapkus as Stuart’s girlfriend, Denise, Brian Posehn as a geologist named Bert Kibbler, and John Ross Bowie as a physicist named Barry Kripke.

Along with those returning recurring characters, it was also announced that a few one-off characters are also returning for the spinoff. One of those characters is played by an actor who is quietly becoming the king of appearances in Chuck Lorre’s sitcom universe.

Ryan Cartwright Chuck Lorre Show Kevin Can Wait wearing gray suit looking surprised

The Stuart Spin-Off Will Be Ryan Cartwright’s Fifth Chuck Lorre Show

Ryan Has Become An Important Part Of The Lorreverse

Stuart Fails to Save the Universealso marks the return of actor Ryan Cartwright, who has become the face of Chuck Lorre shows by appearing in many of them. Ryan first appeared in the 2014 show,Mom, playing the role of Jeff Taylor. He appeared in four episodes to establish himself in Chuck Lorre’s sitcom universe.

Cartwright later appeared inBob Hearts Abishola. He made only a guest appearance in the show, but it made him one of the few actors to appear in multiple shows by Chuck Lorre. He then joined the cast ofB Positivein 2022. He played the role of Asher for two episodes, leaving a lasting impact on the show and becoming a standout in the Lorre universe.

The Big Bang Theory Poster

Now, the actor is set to appear inStuart Fails to Save the Universeas Kyle, a role he previously played inThe Big Bang Theory. This newest role brings his total number of Chuck Lorre shows to five, a sneakily impressive record for the versatile TV actor.

Cartwright’s Previous Big Bang Theory Guest Spot Came In Season 6

Ryan Played The Role Of Penny’s Friend

Ryan made his most notable appearance onThe Big Bang Theoryin the season 6 episode"The 43 Peculiarity," as Penny’s British classmate, Cole. The story of the episode depicts Leonard becoming jealous of Cole due to his close relationship with Penny.

Despite Ryan’s brief and one-time appearance onThe Big Bang Theory, it solidified him as a recurring cast member in Chuck Lorre’s shows. Now, fans almost expect him to appear in every show within the Lorreverse. It’ll be interesting to see Ryan appear inThe Big Bang Theoryspin-off,Stuart Fails to Save the Universe, if only to see if Cole has changed, and if so, how.