'Big Bang Theory': How That Surprise Guest Ended up in the Series Finale

The Big Bang Theory aired its series finale on Thursday, May 16, and the show had a few surprises for fans up its sleeve for its final offering, including a special guest star.

The episode saw a cameo from Sarah Michelle Gellar, who played herself and accompanied Raj to Sheldon and Amy's Noble Prize acceptance ceremony in Stockholm, Sweden. The two had met on the plane from Los Angeles and the actress agreed to accompany Raj to the event.

Her appearance was a surprise to the characters as well as the audience, with Sheldon exclaiming in the middle of his speech, "Is that Buffy the vampire slayer?"

Executive producers Steve Molaro and Steve Holland opened up about the cameo to Entertainment Tonight, sharing that series creator Chuck Lorre thought the empty plane seat next to Raj could make for a fun moment.

"We knew that they were going to be on the plane and that there was no one sitting next to Koothrappali," Molaro said. "Then Chuck was like, 'This seems like an opportunity for him to be sitting next to somebody fun. Maybe there's a celebrity that we can incorporate into this.'"

"I mean, Steve and I are both big Buffy fans — as are a lot of people in the [writers'] room," Holland added. "And rather than going for whoever is the hot 'right now' celeb, it seemed like a really cool, nerd-pull for these characters who have been fans of Buffy forever too. And it was our way to get to meet her before the end."

The show has had a long history of Buffy references, and it turns out that Gellar was a fan of the sitcom, making it an easy choice for her to accept the cameo request.

"Chuck spoke to her, but it's always a good sign when the first thing people say is, 'Our family are huge fans of this show!'" Holland said. "That was how it went with Sean Astin too. We reached out and he's like, "Our family are gigantic fans, we watch every week!" So then it's like you're pretty safe and then it was just a matter of working out scheduling [with Sarah.]."

The duo added that they filmed Gellar's guest spot one day before the finale aired, so while they did request that audience members keep the cameo a secret, they didn't have to stay quiet for too long. They also explained her line to Raj, when she made sure to tell him that they weren't on a date.

"It seemed funny," Molaro said. "We know in real life she's married to Freddie Prinze Jr. and, obviously, it's a TV show, but it was just a funny way to cover our bases and get a joke in and give her a good laugh along the way."


Photo Credit: Getty / CBS Photo Archive