Penny from Big Bang Theory

For those of you who live under a rock, "The Big Bang Theory" has become one of television’s most beloved sitcoms. The series follows a group of "nerd" physicists and engineers who have everything going for them except for basic social skills. That all changes when Penny moves in across the hall from their apartment. She introduces the boys to a fresh new perspective, which allows every character in the series to open up to new potentials and possibilities. Their friendship is at the core of the show, which makes Penny the glue that holds the series together.

Because of this, we’ve chosen to take a closer look at Penny from "The Big Bang Theory." While the sitcom ran for a total of 12 seasons — winning a pile of Emmys and nominations for the cast and crew (via Emmys) — there is still lots about the show that remains unexplored, much of which centers around Penny (Kaley Cuoco), the free-spirited neighbor of the Sheldon (Jim Parsons) and Leonard (Johnny Galecki).

Let’s dive into some untold truths about Penny. Penny. Penny from "The Big Bang Theory."

Penny’s last name is revealed in an unexpected way

Penny sitting on a couch

A common misconception about Penny is that her last name is never revealed. The Daily Express detailed a few fan reactions and questions regarding Penny’s surname before she marries Leonard and takes his last name, Hofstadter. However, Penny’s last name is actually revealed in Season 2’s Episode 18, "The Work Song Nanocluster." According to CBR, Penny gets a package delivered to her when she’s attempting to start Penny Blossoms, her own flower barrette company. On the packing label of the package, her full name — Penny Teller — is visible for audiences to catch. You definitely have to squint a little bit, but upon a close-up inspection of the package, it looks more or less like it’s addressed to a "Teller."

What’s most interesting about this little tidbit of information is that back in 2019 at WonderCon’s panel for "The Big Bang Theory," when executive producer Steve Molaro was asked about Penny’s last name, he responded, "We got nervous and superstitious about giving her one." Perhaps he forgot about that small blink-and-you’ll-miss-it detail from Season 2.

Penny’s sister Lisa is never shown

Penny and her family

Penny is a character who likes to talk, and her family is one of her favorite subjects for discussion. There are plenty of stories to go around when it comes to Penny’s colorful childhood, and one character who comes up frequently is her sister Lisa. Audiences know that Lisa is married, has a son, and that Lisa discovered Penny’s ex-boyfriend’s Twitter account that detailed his sex life with Penny. But here’s the twist — audiences have never seen Lisa.

Lisa is the only family member who doesn’t make it to Penny and Leonard’s wedding, which feels exceptionally odd. Judging from the number of times Penny mentions her sister in the series, they seem close. And yet, somehow the audience meets Penny’s brother Randall (Jack McBrayer) — a meth dealer who spends the majority of the show in prison — but not her sister.

Penny wasn’t originally supposed to be in the show

Katie writing on a whiteboard and talking

As the literal geniuses of "The Big Bang Theory" can be difficult for most audience members to relate to, Penny serves as someone more-or-less normal viewers can connect with. However, Penny wasn’t always meant to be in the series. In the original unaired pilot, Penny’s role on the show is filled by Katie, a completely different character played by Amanda Walsh.

According to ComicBook, Katie was described as being "a street-hardened, tough-as-nails woman with a vulnerable interior." However, all the networks passed on this Penny-less version of show, including CBS which later became the sitcom’s home for 12 successful years. In a DVD special feature, Kaley Cuoco revealed that when she originally auditioned for "The Big Bang Theory," she didn’t get the part, as Katie was more of a brooding character. However, once the show cut Katie and replaced her with the bubbly Penny, Cuoco was a lock for the gig. In fact, Cuoco had previously played a similar character on the successful family sitcom "8 Simple Rules."

Penny was hard for Kaley Cuoco to let go

Penny frowning in a suit

You know it’s a good sign for a series when the cast has to struggle to move on after it ends. And that’s exactly what happened for Kaley Cuoco when the end of "The Big Bang Theory" was announced. Cuoco told Variety about her experience when she was brought into a meeting and told that she would be saying goodbye to Penny sooner than expected. Cuoco recalled that it was the summer of 2018 and the cast had just begun shooting for Season 12. She and co-star Johnny Galecki assumed the conversation was pertaining to the next season, and she remembers the two actors being excited to continue with their characters. However, that’s not what the conversation was about.

Instead, Jim Parsons said he was done with the show. Then creator Chuck Lorre announced if they weren’t all in, it made sense to say goodbye. That meant that Season 12 would be the final season, leaving Cuoco in what she described as "a state of shock." She noted that there were many tears, especially in the final episode, from the entire cast and crew. She also shared that her father attended every tapping of that season.

Penny once built an entire tractor engine

Penny sitting cross legged

Although Penny is usually seen as a relatable character for audiences, she’s often used as the butt of the jokes on "The Big Bang Theory." Although the gang bring the best out of each other in theory, in practice Penny is often looked down on for not being as smart as the other characters. Leonard and Sheldon are physicists, Howard (Simon Helberg) is an aerospace engineer, Raj (Kunal Nayyar) is an astrophysicist, Bernadette (Melissa Rauch) is studying microbiology, and Amy (Mayim Bialik) has a Ph.D. in neurobiology. Meanwhile, Penny spends the majority of the show working as a waitress and struggling actress, but just because she doesn’t have a fancy nerd job doesn’t mean she’s a moron.

In the Season 1 episode "The Big Bran Hypothesis," Penny has Sheldon, Leonard, Howard, and Raj in her apartment to help her put some furniture together. Despite their "superior intellect" they make the entire endeavor much more complicated than it needs to be. At that point Penny tells them, "I grew up on a farm, okay? I rebuilt a tractor engine when I was, like, 12. I think I can put together a cheap Swedish media center." Unfortunately, they don’t listen to her and carry on about their business, leaving Penny behind as they work.

Penny called herself a vegetarian … but she isn’t one

Sheldon feeding Penny

In the first official episode of the series, Penny is hanging out with Sheldon and Leonard in their apartment having lunch. As the three characters are getting to know each another, she tells them that she’s a vegetarian except for when she eats fish. She also mentions that she considers steak an exception to her vegetarianism, because she absolutely loves steak. This prompts Sheldon to say, "that’s interesting" and share the fact that Leonard is unable to digest corn.

While both moments are funny, it’s clear that Penny’s eating habits are played as the bigger joke. She’s clearly not a vegetarian, and there’s no other mention of Penny being a vegetarian throughout the show. Audiences see the group of friends constantly sharing meals in their apartments right up until the final season of "The Big Bang Theory," and Penny definitely doesn’t always stick with meatless options.

Penny’s the only main cast member to miss two episodes

All Big Big Theory characters

According to The Hollywood Reporter, "The Big Bang Theory" has a total of 279 episodes across its 12-season run, and the entire main cast appears in every single episode … except for Penny. There’s an interesting reason why this happened — Kaley Cuoco broke her leg and detailed the story behind the accident on the Ellen DeGeneres Show in 2020.

Entertainment Weekly reported that Cuoco said she was horseback riding and was thrown off her horse. Luckily, she was okay and laughed the moment off. Unfortunately, the horse was still spooked by the incident and attempted to jump over Cuoco, landing right on her leg by accident. Cuoco was immediately taken to the hospital where the doctors were so concerned about infection that they even brought up the option of amputation. Luckily, they ended up putting two metal bars in her leg instead, resulting in a two-week hospital stay that mandated Penny be written out of two episodes of the show. Once Cuoco returned to set, the writers gave Penny a bartending job so that the actress could be shot from the waist up, instead of writing her injury into the story.

Penny might have a drinking problem

Penny getting wasted

Penny isn’t one to shy away from a good bottle of wine, but there are many times when fans and even characters in the sitcom have questioned if she’s had one too many. This has been brought up on Reddit a few times, with users questioning if the character demonstrates some degree of alcoholic behavior. However, the show plays Penny’s above-average love for booze as more of a joke rather than a serious infliction.

In the Season 7 episode "The Locomotive Manipulation," Sheldon, Amy, Howard, and Bernadette take a romantic Valentine’s weekend getaway to Napa Valley, aka wine country. Penny and Leonard make the decision not to join their friends, as Leonard says, "I’m not sure it’s such a great idea to take Penny to where wine comes from." Shots fired, Leonard. Way to call out your girlfriend’s possible substance use disorder in front of all your friends.

If you or anyone you know suffers from substance abuse, please visit the Substance Abuse and Mental Health Services Administration (SAMHSA).