Mark Hamill Has One Regret About His Big Bang Theory Appearance

"The Big Bang Theory" brought on a ton of incredible guest stars throughout its 12-season run — including a ton of actors from the "Star Trek" franchise alone — but one of the most exciting cameos had to be courtesy of Mark Hamill, the man famous for playing Luke Skywalker in "Star Wars" who appeared in the season 11 episode "The Bow Tie Asymmetry." According to a tell-all book about the show, though, he has one huge regret about his appearance on the series.

Hamill, playing himself, ends up encountering Howard Wolowitz (Simon Helberg) after Howard finds Hamill's lost dog, appropriately named "Bark Hamill" — and then offers Howard a favor. Howard gleefully cashes in on that favor by getting Hamill to officiate the wedding of his friends Sheldon Cooper (Jim Parsons) and Amy Farrah Fowler (Mayim Bialik) ... but as Hamill told Jessica Radloff in her book "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," he was pretty unfamiliar with the series itself for a while.

"I didn't really stick with the series early on," Hamill admitted, saying that he actually got back into it while filming "The Last Jedi" in England. "I would have to do the treadmill, and I would notice on Saturdays and Sundays, one of the TV stations would air four-hour blocks of 'Big Bang,' he continued. "By that time, there were so many episodes I had not seen, so I would do the treadmill and measure them in, 'Well, I'll do one episode's worth on the treadmill.' And then, 'Oh, I'll do two episodes' worth on the treadmill,' followed by three." When all was said and done, Hamill said he had probably seen somewhere around 30-40 episodes before he guest-starred on the series but wished he had seen more before making an appearance. "It took me months and months and months, but I've seen them all now," he confessed.

Clearly, Mark Hamill knew he was behind the curve with "The Big Bang Theory," but he made up for it in the end — and as a "Star Wars" veteran and a pop culture lover himself, he ultimately came to really love the show.

"I knew they referenced all kinds of pop culture, and the characters loved comic books, science fiction, fantasy [...] but I had no idea how ingrained it was and how they could be so subversive in their humor," Hamill told Jessica Radloff, praising the show's acerbic attitude towards things like, say, the "Star Wars" prequels. "Like, they're planning a day to watch all the movies and they said, 'Well, you know, we're starting out with "Phantom Menace" at noon and I'm just wondering if an hour is long enough to schedule for complaints.' I thought, Wow, that's a burn! Very clever."

In fact, Hamill said that he wished he had known more about the show before appearing on it because he could have chatted with the cast and crew about the many, many episodes that referenced "Star Wars" or its creator, George Lucas. "Once I knew all of this, it would have really changed my experience. I would have talked to them about when they go to [Lucas' home] Skywalker Ranch, or [the season 9 episode "The Opening Night Excitation"] where it opens with the crawl from ["Star Wars"]," Hamill mused. "I thought I'd seen plenty when I did my episode, but I became a completist and saw them all. I didn't really become enamored of it to the degree I had become until I had the experience of being on the show. I became obsessed with it."

The bit with Howard and Bark Hamill is just the start of Mark Hamill's turn on "The Big Bang Theory," because as I mentioned, the whole thing culminates in Hamill officiating Sheldon and Amy's long-awaited wedding. This part of the episode is actually a ton of fun; everyone watching the ceremony is losing their mind over the presence of Luke Skywalker and keeps asking him in-depth questions about "Star Wars," many of which he can't even answer. (Luckily, Stuart Bloom — played by Kevin Sussman, who nearly snagged the role of Howard — knows the answer to pretty much all of them.) Then, during the actual vows, Hamill is so overcome by how touching Amy and Sheldon's speeches are that he cries ... which is sort of beautifully undercut when Sheldon asks Hamill to autograph a million things after the ceremony ends.

Hamill, for his part, loves it — and his emotions were apparently real. "That was a cultural, pivotal moment in pop culture," Hamill recalled. "I didn't expect the emotion of the moment to happen to me, so when it did, I got choked up. The whole episode was just so effortlessly well done. I love when Sheldon says, 'I have four thousand things for you to sign.' Jim Parsons is brilliant, but that whole cast, really, is just perfection."

"It was really nice to have him there," Parsons agreed, saying that even though the cast had only just met Hamill, it worked wonderfully. "For such a big scene, it was oddly intimate. And you have this person involved in a major moment who you don't know that well and who's never been on the show before [...] I kind of enjoyed that presence with us. It was beautifully odd!"