Warning! Spoilers ahead for Young Sheldon season 5, episode 7.
Howard Wolowitz's cameo in Young Sheldon supports a popular theory about The Big Bang Theory. Simon Helberg revisited his sitcom roots when he reprised his role as one of Sheldon's (Jim Parsons) Pasadena friends in the CBS spin-off series. But aside from the pair's bickering, which is always fun to see, Howard's Young Sheldon cameo also solidified a popular theory that Sheldon is actually in the process of working on his autobiography post-The Big Bang Theory.
Helberg followed Kaley Cuoco and Mayim Bialik in recording a cameo for Young Sheldon via voiceover. Unlike his predecessors, CBS actually promoted Howard's guest appearance, prominently using his part in the network's marketing campaign. While he was only in the episode very briefly, it was more than enough to excite fans of The Big Bang Theory who sorely miss the show almost three years since it went off the air in 2019. When the sitcom ended it was still a rating juggernaut for the network, but when Parsons decided it was time to exit the series the cast made the difficult call to wrap things up. Naturally, fans are always thrilled to learn about what the Pasadena gang is doing since the sitcom's finale by way of its popular off-shoot.
Admittedly, Howard's cameo in Young Sheldon season 5 "An Introduction to Engineering and a Glob of Hair Gel" was disappointing. It didn't live up to the hype since much of his involvement was already spoiled in marketing. That being said, it teases something more important with regard to how the spin-off actually relates to its parent series. When Young Sheldon premiered in 2017, questions about why adult Sheldon was narrating the events of the show arose. There hasn't been any official information about the matter, but there's a theory that it's because adult Sheldon is in the process of working on his autobiography, and this is his way of recalling all the important experiences from his childhood. During Howard's appearance in Young Sheldon, he mentioned that his friend asked him to write an introduction to engineering as part of Sheldon's story. It hints that there's actually a rhyme and reason to his stories and that his narration is a part of a big project that chronicles the character's life.
Since Sheldon has an eidetic memory, it's not outside the realm of possibility that he still remembers all these things from his days living in Pasadena. In fact, it would only make this endeavor much easier for him. Young Sheldon has yet to reveal how far into the future the narration is set, but based on Sheldon's revelation about having a son named Leonard Cooper, it's been more than a decade since the events of The Big Bang Theory finale. Not much is known regarding the life he's been leading since his work on Super Asymmetry with Amy (Mayim Bialik) was recognized, but as a Nobel Prize winner, it makes sense that people would be interested in learning more about his life, and his time in Texas was a big part of that.
With more than two seasons to go, the still-popular Young Sheldon is confirmed to run for at least until the 2023-2024 TV season, which means that there's still plenty of time to bring in other The Big Bang Theory stars for a cameo. While having anyone from the Pasadena gang would be a treat, seeing Sheldon reunite with his best friend Leonard (Johnny Galecki) would be the most interesting one. And at the very end of the spin-off, perhaps CBS can show adult Sheldon celebrating the release of his autobiography in Pasadena.