Alongside her castmates, 43-year-old Bialik appears on Thursday's The Ellen DeGeneres Show, where she reveals her initial misconception about the series. The interview comes months after CBS revealed that the show's 12th season will be its last.
"I had never seen The Big Bang Theory. I thought it was a game show," she confesses. "Someone had told me that in some season of The Big Bang Theory they mentioned that the girl from Blossom is a scientist. So when somebody told me that I thought, 'Oh, it must be a game show, like, a trivia thing.'"
"I had no idea that it was a very popular sitcom, apparently," she adds. "My manager said, 'They're looking for a female Sheldon Cooper,' and I said, 'Who's Sheldon Cooper?'"
Though all of the main cast -- which includes Kaley Cuoco, Johnny Galecki, Jim Parsons, Simon Helberg, Kunal Nayyar and Melissa Rauch -- is emotional about the series' end, it's Cuoco who's found herself the most affected.
"We've been getting super emotional. We were doing a scene before the holiday and we were just blocking and we were the only two in it and just kind of rehearsing the scene and out of nowhere I just started bawling," Cuoco, 33, says of a scene with Galecki, 43. "And the crew, all the camera guys and everyone, came out, they're like, 'We're so glad you cried because we've been waiting to cry.' And then they all gave us this huge group hug and we just all cried for, like, 10 minutes."
Parsons has yet to find himself breaking down over the show's end, but he knows it'll happen sooner or later.
"I haven't cried yet and I have a very deep fear, seriously, that the most unexpected thing is going to happen [and] I'm gonna absolutely lose my sh*t," Parsons, 45, says. "Because it really is profound, the amount of time of your life. And I think it's, like, more than any of us can get a grip on and I'm worried that something's going to trigger me deep down inside."
When ET's Nancy O'Dell caught up with Cuoco at the Golden Globes earlier this month, she confessed, "I don't wanna leave," before revealing that she'd certainly be up for a reboot.
"Everyone’s doing rebooting. We might as well do it in, like, a year!" she quipped, later confirming when O'Dell asked if she was really open to revisiting her character, Penny, in "one year." "I'm fine with that!" Cuoco said.
Watch the video below for more on the show's final season: