The cast of The Big Bang Theory couldnt contain their feelings during a Thursday appearance on The Ellen DeGeneres Show, telling the host they were getting emotional about the upcoming conclusion of their beloved sitcom.

Last August, CBS executives confirmed that season 12 of The Big Bang Theory would be its last. At 279 episodes, the show is set to make television history as the longest-running multi-camera comedy series of all time.

Jim Parsons, who stars as Sheldon Cooper, told DeGeneres hed yet to feel sentimental about the series finale, which airs in May, but that he expects to do so.

I have a very deep fear, seriously, that the most unexpected thing is going to happen, he said. And Im going to absolutely lose my shit because it really is profound, the amount of time in your life.

Its like more than any of us, I think, can get a grip on, he continued. And Im worried its going to trigger something deep down, like, Oh, I didnt know that was there! Oh, that hurts, you know?

Kunal Nayyar, who plays Raj Koothrappali, had a more pragmatic take.

When well be unemployed, well really be crying, he quipped.

Since its 2007 debut, The Big Bang Theory has become an entertainment colossus, earning 52 Emmy Award nominations and airing in syndication around the world. A spinoff prequel, Young Sheldon , debuted on CBS in 2017, starring Iain Armitage as the 9-year-old version of Parsons character.

Along the way, The Big Bang Theory has amassed a devoted fan base, which includes plenty of aspiring scientists.

Mayim Bialik, who plays Amy Farrah Fowler, said that being able to put a different face on science and scientists for young viewers felt especially impactful.

After rocketing to fame in the 1990s as the title character of the NBC series Blossom, Bialik herself earned a Ph.D. in neuroscience from the University of California, Los Angeles.