Kevin Sussman has revealed that a single improvised line helped completely change the direction of Stuart Bloom on The Big Bang Theory. Originally introduced in Season 2 as a relatively normal, soft-spoken comic book store owner, Stuart gradually became one of the show’s most unfortunate — and oddly lovable — characters.
Speaking at the 2021 Paris Manga & Sci-Fi Show, Sussman pointed to a moment in Season 3’s “The Guitarist Amplification” that shifted everything. In a scene where Penny visits the comic book store, Sussman went off-script as she walked out and quietly muttered, “I love you.” The line wasn’t written, but it caught the writers’ attention immediately.
According to Sussman, that small improvisation helped define Stuart’s “regressive” arc, pushing the character from socially awkward into increasingly desperate territory as the series went on. What began as a one-off joke ultimately reshaped Stuart’s role across multiple seasons.
Sussman is set to reprise the character in the upcoming HBO Max spin-off Stuart Fails to Save the Universe, slated for release in 2026, alongside fellow Big Bang Theory alumni Lauren Lapkus, Brian Posehn, and John Ross Bowie.
