'The Big Bang Theory' Cast Reflects on Their 12-Year Run Ahead of the Big Farewell

Jim Halterman
Preview Jeff Lipsky

Kaley Cuoco's unreserved laughter rings through the cool February air in Culver City, California, where she stands alongside costar Johnny Galecki during their final TV Guide Magazine cover shoot for The Big Bang Theory. The beloved hit CBS comedy, about a group of science nerds and the women who love — and challenge — them, will air its 279th and final episode on May 16. Cuoco's upbeat mood is helping to keep sadder feelings about the show's end at bay…for now.

The actors, whose Penny and Leonard commenced their spirited on-again, off-again relationship all the way back in Episode 1, tease each other between shots. "You have green eyes. I just noticed!" he says. She replies: "Twelve years! You didn't know my freaking eyes were green?"

(Jeff Lipsky)

But when the subject turns to Big Bang's one-hour finale, set to shoot on April 30, fear flashes across their faces. "I'll have to go on autopilot to a certain degree to get the show done," says Galecki. Cuoco adds, "I'm devastated. It's gonna kill me slowly."

And to think, one of the most popular series in history almost didn't make it on the air. A failed pilot for the 2006–07 season starred Galecki as nebbishy experimental physicist Leonard Hofstadter and Jim Parsons as his prickly roommate, theoretical physicist Sheldon Cooper; nobody else from the current cast was involved. But CBS executives saw a glimmer of something.

Behind the Scenes of the 'Big Bang Theory' Cover Shoot With Kaley Cuoco & Johnny Galecki (VIDEO)

Behind the Scenes of the 'Big Bang Theory' Cover Shoot With Kaley Cuoco & Johnny Galecki (VIDEO)

The stars sat down with us to talk wrapping up the iconic shows. Plus, they shared some favorite memories!

The pilot was retooled, adding Cuoco's struggling actress (now a pharmaceutical rep) Penny (her last name has never been revealed), plus the roommates' equally geeky friends, aerospace engineer Howard Wolowitz (Simon Helberg) and astrophysicist Rajesh Koothrappali (Kunal Nayyar). Big Bang premiered on September 24, 2007, and quickly built a fan following. The sitcom peaked at an average of 20.4 million viewers for the 2015–16 season, earned 52 Emmy nods (with four lead actor in a comedy wins for Parsons) and launched a hit prequel (Young Sheldon). 

So how did a show that made nerds cool become such a phenomenon? "The Big Bang Theory uniquely brought tens of millions of people together every Thursday night," says Kelly Kahl, president of CBS Entertainment. "I think the longer the show ran, the more the audience saw of themselves in the characters." With weeks left to go, the gang looks back.

Jim Parsons: I recall feeling like I was walking on a tightrope for that first audition. The dialogue was so dense — to me, at least — and had lots of multisyllable words. I had never met Johnny, [but] as soon as we read through the scene, I thought he was the one. I just felt it. Thankfully, everyone else agreed.

Peter Roth (president/ chief content officer, Warner Bros. Television Group): In the first pilot, the character of Penny [originally named Katie] was not as appealing as that proverbial girl next door. It was not the actress [Amanda Walsh] but rather the conceit of the character. Fortunately, Nina Tassler, then-president of CBS Entertainment, realized we had something very special and said, "Let's do it again."

Kaley Cuoco Shares Her Favorite 'Big Bang Theory' Episodes & Post-Finale Plans

Kaley Cuoco Shares Her Favorite 'Big Bang Theory' Episodes & Post-Finale Plans

Plus, the actress looks back on Penny's legacy and her mysterious last name.

Cuoco: I didn't get [the role of Katie] the first time around. I was too young, which I love saying because I don't get to say that I'm too young anymore. [Laughs] Then, a year later, I heard they were doing it again, and they brought me back in to read for Penny.

Bill Prady (cocreator/executive producer): The triangle in the pilot [between Leonard, Sheldon and Penny] is more than just romance; it's the core of the show. You've got Leonard with two forces pulling at him — Sheldon, who is pulling him away from the world, and Penny, who's essentially pulling him out into the world. She's an irresistible force. 

Galecki: I really liked the dynamic between Leonard and Penny and I knew they were going to navigate all those territories of on-again, off-again love. That was clear from the page before I even met Kaley.

(Credit: Sonja Flemming/CBS)

Cuoco: As the seasons went on, you could tell that the Leonard/Penny relationship was not going to be conventional, which I loved. It felt very real. There was a crush, they went out, then they didn't and then they both had different relationships. [They finally married in Season 9.]

Galecki: It felt very natural, almost musical, [to reshoot] the pilot when Kaley was on board with Simon and Kunal. It felt like a band you'd been playing with for years. And everything that everyone did complemented what someone else had to do. It was just fantastic. There's no recipe for that kind of chemistry. 

Parsons: [Adding Raj and Howard] expanded our world, our story possibilities. Midway through the pilot, just when you think you've met everyone, in pop Simon and Kunal, and it's just magical.

Jim Parsons Lines Up Post-'Big Bang Theory' Project at Netflix

Jim Parsons Lines Up Post-'Big Bang Theory' Project at Netflix

The comedy series is set to debut this spring on the streaming service.

Helberg: When Kunal and I entered — and, remember, this was our first time ever on camera as these characters — the [studio] audience erupted, and they didn't even know who we were! They were so excited that there were more like Sheldon and Leonard. The director had to stop and wait for the audience to calm down.

Even in those early days before the explosion of social media, the cast realized viewers were finding the show — and loving it. 

Helberg: Around Episode 8 or so, audience members started showing up with homemade memorabilia. I had mentioned in an interview that I was trying to learn how to cook, and a young woman showed up with an apron that had my face on it and referred to herself as a member of "Howard's Harem." 

(Credit: CBS)

Nayyar: We would look at the ratings and get a sense that we were at least competing with the other shows in our timeslot.  

Cuoco: I remember we were in Hall H when we went to San Diego Comic-Con [in 2010]. Hall H [which seats 6,500 people] is the biggest hall there! 

Galecki: I said to Chuck [Lorre, cocreator and executive producer], "They need to put us in a 300-seat theater!" But people had camped out overnight to be inside. It was amazing. 

The ensemble expanded in Season 3 with the additions of microbiologist Bernadette Rostenkowski (Melissa Rauch) and neurobiologist Amy Farrah Fowler (Mayim Bialik) as love interests for Howard and Sheldon. 

Rauch: When Bernadette was introduced, she was sheltered [and had an] overbearing mother, much like Howard. 

Will There Be a 'Big Bang Theory' Spinoff? Chuck Lorre on the Show's Ending, Penny's Intelligence & More

Will There Be a 'Big Bang Theory' Spinoff? Chuck Lorre on the Show's Ending, Penny's Intelligence & More

Lorre and EP Steve Holland talk who we might be seeing again before 'TBBT' concludes, Sheldon's turning point, and a lot more.

Helberg: Bernadette cut through Howard's sleaze like a fine dish soap removing the grease. Melissa and Mayim caused this whole sea change in the show. The layers they brought to Big Bang are really a fundamental part of the show's success, because they humanized all the characters that much more. 

Roth: The introduction of Amy in particular was one of the funniest things I've ever seen. To see the perfect realization in female form of Sheldon was hilarious. And Mayim embodied her so perfectly. 

Bialik: I remember being nervous because the cast had been working together for three years, so they had a really good rapport. I only had maybe five lines [in Amy's first episode], so there wasn't a tremendous amount to do, but it was really fun. 

(Credit: Michael Yarish/CBS)

Parsons: I thought it was such an original idea, the way they brought Amy in. [Raj and Howard had signed Sheldon up for an online dating site.] 

Rauch: The female camaraderie among Penny, Amy and Bernadette has played
a significant role for all of them. It was during some of their first girls' nights that we got more of a taste of Bernadette's sass.

As it became a pop-culture phenomenon, the show launched catchphrases ("Bazinga!," "You're in my spot") and a song (Sheldon's lullaby "Soft Kitty") and attracted a slew of guest stars — many from the science and comic book worlds the characters adored.

Parsons: The first person Sheldon tasks with singing "Soft Kitty" is Penny, which just adds more glorious oddness. I think that's part of the reason some viewers hold it so dear. 

Jim Parsons on 'The Big Bang Theory' Ending: 'It Was Time'

Jim Parsons on 'The Big Bang Theory' Ending: 'It Was Time'

Plus, he joked that he was getting a little old to wear T-shirts and make it believable.

Galecki: I remember we were trying to figure out the melody to it onstage and Bill Prady came down with a recorder and played it for us, and we just reached another echelon of nerdy. 

Cuoco: I was like, "Where the hell did this song come from?" And everyone knows the words but me!

Parsons: I had never heard the word bazinga before. It sounds like a word some not-good comedian would say, no? And that is definitely one way to describe Sheldon, a "not-good comedian."

Steven Molaro (executive producer): Rarely did we [cast a guest] actor and then work backward to find a story. We also learned to be sensitive to the concerns of any actors we asked to play a version of themselves. It's one thing for an actor to play a role — it's another for us to say, "Hey, Wil Wheaton, would you come on our show as yourself, but we need you to play a complete d--k."  

Wil Wheaton: It's always fun to play the villain because we get to imagine things we'd never do in real life. I would never mess with someone's relationship to win anything — much less a bowling match [in Season 3's "The Wheaton Recurrence"]. I especially love that episode because it was peak "I'm living in Sheldon's head, rent-free" for me.

(Credit: Monty Brinton/CBS)

As the characters matured, they experienced a painful loss…

Molaro: The death of Howard's mother [in Season 8] held significant meaning to us because our real-life friend Carol Ann Susi [who voiced the never-seen Mrs. Wolowitz] had sadly passed away. We couldn't imagine anyone else doing the voice of that character and made the decision to say goodbye to Mrs. Wolowitz.  

Helberg: The challenges for me were in the same realm as the challenges for Howard. The cast and crew were mourning her loss in real time.

Molaro: The day she passed away, Johnny Galecki and I put a small picture of her on the refrigerator in the guys' apartment so she could be in every episode. I still get choked up whenever I look at it.

This is an abbreviated version of TV Guide Magazine's latest cover story. For more from our conversation with the cast of The Big Bang Theory, pick up the issue, on newsstands now. And stay tuned to TV Insider for exclusive behind-the-scenes photos from the cover shoot with Kaley Cuoco and Johnny Galecki!

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