Iconic sitcoms are not easy to wrap up, especially when it comes to leaving all fans happy. Whether it be 'Friends' or 'Big Bang Theory', fans will always question certain moments and how things should've been done.

For the final 'Big Bang' episode, everything needed to be just right and that included the celeb cameos. For the producers and creators, it was important that it wasn't just any popular celeb taking part in the final episode.

It needed to be someone with a certain history on the show, enter Sarah Michelle Gellar.

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The cameo was a great part of the show, as she sat alongside Raj.

We'll dive into the context behind the appearance. Why was she selected along with why she accepted the role we'll all be touched upon throughout the article.

In addition, we'll dissect if Gellar was more content taking on the role than a certain reboot from her past.

'Big Bang' Didn't Want Just Any Celeb For The Finale

Following a run of over a decade, matched with 12 seasons and over 275 episodes, it was only right that the final episode needed to be just right, and that included celeb cameos. Turns out, the show wasn't looking for just any major star during its final episode, it needed someone that would fit the bill.

Given the constant 'Buffy' references throughout the show's run, it was only right that Sarah Michelle Gellar was asked to come on board alongside Raj.

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Executive Producer Steve Moalro discussed the casting process and why Gellar was picked for the role.

‘Chuck [Lorre] 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."

"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."

It all worked out and it made for a memorable cameo on the show. As it turns out, the celeb was just as excited to appear on the show.

Gellar Wanted To Evolve From 'Buffy'

Similar to so many other actors in the business, Gellar revealed alongside Female that she has a desire to not be typecast in a similar role - aka 'Buffy'.

"I hope I've evolved a lot. I know, from the first season to the eighth season I grew tremendously as an actress and a person. For me, that's the journey that I hope to continue on, so I hope I've evolved, otherwise, I'd be pretty boring to watch."

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Now we can't say for sure, but it seems apparent that Sarah Michelle Gellar had a bigger interest in working the cameo appearance on 'Big Bang' as opposed to a 'Buffy' reboot. She discussed being hesitant about a 'Buffy' type reboot.

"I have to be honest. That thought really scares me. Buffy was a movie and it didn't work because her story was longer than that. This was about a girl that you had to get to know and it took so long to figure out how to crack the ending so that people weren't upset. Of course, I never say never, so I'm not saying no, but my fear would be to open something like that up again, to only end it again."

Who knows what the future holds but at the moment, she's having fun being selective with her work while immersing herself in different roles.

She Was Honored To Take Part In 'Big Bang'

Gellar was asked to work a completely different role, in the world of comedy. Some would steer clear of the opportunity, but that clearly wasn't the case for the actress. She was contacted and given the context of her role, she was told all about the long-running gag throughout the show's run. Gellar didn't hesitate to accept and as she revealed alongside TV Insider, the star had a blast during her time on set.

“I got the phone call and, they said, ‘You’ve been such a recurring gag on the show, would you like to help us end it?’ and I thought, ‘Oh my goodness,'” Gellar recalls. “I love that cast and we had a great time. I was honored to be a part of it and be part of the legacy of such an incredible show.”

It all turned to be great and the finale was adored by most fans. Who knows, maybe if 'Big Bang' works a reboot, she'll appear once again.

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