It’s been three years since the final episode of The Big Bang Theory aired, but its popularity hasn’t waned. With constant reruns on TV and finding new life on streaming services, Pasadena’s favorite scientists and waitresses are never far out of reach. The adventures of Sheldon, Leonard, Howard, Raj, and Penny never fail to bring out laughs, awkwardness, and geeky goodness.
As one of the most successful sitcoms of all time, Big Bang secured some pretty high-profile guest stars throughout the show’s run. These stars impressed us with their comedic chops, featuring Star Wars actors, superhero icons, and Oscar winners, and were an absolute delight to see with these beloved characters.
10) Billy Bob Thornton
Hollywood heavyweight Billy Bob Thornton plays Dr. Oliver Lorvis, a pharmaceutical client of Penny’s, in an episode from the show’s eighth season. After a misunderstanding, Dr. Lorvis hopes to initiate a romantic relationship with Penny but bonds with the guys instead.
Thornton is hilarious as the creepy and socially clueless doctor, bringing out all kinds of cringe as he hopefully pursues romance with every woman who is nice to him. As a celebrity urologist, he also gains the gang’s trust by showing them strange memorabilia, including James Cameron’s kidney stones.
9) Steve Wozniak
Apple co-founder Steve Wozniak makes a brief appearance as himself during the show’s fourth season. When Sheldon (Jim Parsons) discovers he won’t live long enough to transfer his consciousness into a robot, he tries to increase his lifespan and creates a mobile virtual presence device.
While controlling the device from his bedroom, he bumps into Wozniak at the Cheesecake Factory. Wozniak says he would sign Sheldon’s computer if he were there in person, so Sheldon rushes to meet him but injures himself. It’s a fun cameo, especially when, after his encounter, Wozniak simply says, "Nerds."
8) Regina King
The multi-talented Regina King plays Janine Davis, the university’s Human Resources Administrator, who appears in more episodes later. Because of her position, she is forced to deal with the gang and their shenanigans several times, particularly Sheldon.
King manages to keep her calm and deliver perfect comedic timing during her scenes, especially those alongside Jim Parsons. Sheldon is sent to human resources more than once, and his lack of social and cultural awareness makes for some jaw-dropping yet hilarious moments with Davis.
7) Mark Hamill
Luke Skywalker himself, Mark Hamill, appeared in the finale of the show’s eleventh season, playing a version of his real-life self. When Howard (Simon Helberg) finds his dog, Bark Hamill, the actor offers a favor and agrees to officiate Sheldon and Amy’s wedding as a surprise guest.
It’s a real treat to see the guys finally meet and interact with their hero from their favorite movie franchise. Whether he's taking Star Wars questions from wedding guests or breaking down because of Sheldon and Amy’s (Mayim Bialik) heartfelt vows, it’s a spectacularly nerdy experience.
6) Adam West
The original Batman TV actor Adam West appeared as himself in the show’s 200th episode during season nine. As a child, Sheldon’s sister lied that Batman would attend his birthday, but he never showed up. The gang arranges for West to attend Sheldon's birthday party to cheer him up.
West has some great banter with the characters, particularly in a scene where Leonard (Johnny Galecki), Howard, and Raj (Kunal Nayyar) pick him up and drive him to Sheldon’s party. The group argues and ranks their favorite Batman actors, and when Ben Affleck is mentioned, West says, "What’s an Affleck?"
5) Carrie Fisher
A few actors from Star Wars appeared as guest stars on The Big Bang Theory, and one of those was the legendary Carrie Fisher. In an episode during season seven, Sheldon has a night out with another Star Wars actor, James Earl Jones, who rings her doorbell and runs off.
Fisher was a notoriously funny woman, displayed here as she comes out in her nightgown, wielding a baseball bat and ready to take down Darth Vader himself. It's a very brief appearance but one of the most memorable on the show.
4) Stan Lee
Marvel icon Stan Lee appeared as himself on an episode during the show’s third season. When Sheldon misses out on attending a comic book signing and meeting Lee, Penny tries to arrange another way for them to meet, as Sheldon had to go to court because of her.
Penny takes Sheldon to Lee’s house, where he answers the door in a Fantastic Four robe. It’s an epic appearance and incredibly hilarious when Lee sarcastically asks Sheldon to come in and watch the Lakers game, which Sheldon does. The result? A good old restraining order.
3) Stephen Hawking
The brilliant and inspiring Stephen Hawking, who is one of Sheldon’s scientific heroes, actually starred in a few episodes of the show. The first and most prominent was in season five, where he worked with Howard, and Sheldon got to meet him by doing unfavorable tasks for Howard.
Hawking featured in further episodes of the show through voice-over and appearances on Skype. The scientist had a great presence and even sass to the screen — like when Sheldon faints after meeting him and Hawking, obviously overdramatic people, says, "Great, another fainter."
2) James Earl Jones
James Earl Jones — or "Darth Vader and The Lion King's dad" — gives perhaps the series' wildest and most delightful guest appearance. In season seven, Sheldon tries to create his own convention after missing out on Comic-Con tickets, and meets Earl Jones.
Sheldon and the actor instantly hit it off and have a night out that is perhaps a bit too intimate for Sheldon’s liking. Whether sharing a sundae, doing karaoke, pranking Carrie Fisher, going on a Ferris wheel, or heating up in a sauna, we never thought we’d see Darth Vader like this.
1) Bob Newhart
Veteran actor Bob Newhart gives one of the show’s top performances as Arthur Jeffries. Arthur played Professor Proton in a science TV show Sheldon loved and is also his idol. However, Arthur isn’t so fond of Sheldon and is not afraid to clarify that.
Newhart’s dry delivery and sharp wit are genius and make Arthur more than a basic recurring character. Despite his aversion to Sheldon, the two form a strange bond and even share touching moments. In an episode during season nine, a deceased Arthur appears as a Force Ghost to Sheldon and hesitantly gives him advice.