The Big Bang Theory had quite a few impressive guest stars during its run.
While a handful of guest stars appeared in recurring roles or had a big memorable guest appearance, but others appeared in more quietly.
TBBT ran for 12 seasons, and it actually brought on some incredible guest stars, no matter how big or small the role was. The late Bob Newhart, for example, appeared in multiple episodes as Professor Proton, while the late Stephen Hawking also had a few appearances as himself. Stan Lee, Leonard Nimoy, Sara Gilbert, Wil Wheaton, and Laurie Metcalf also had memorable guest appearances, but there are many more who we never realized were on the show or that we forgot.
Octavia Spencer
Four years before winning an Oscar for her role in The Help, Octavia Spencer had a very brief role in The Big Bang Theory as a DMV employee in Season 2, Episode 5, “The Euclid Alternative” in 2008. She helps Sheldon as he tries to get his learner’s permit, and it’s a pretty funny role, even though it’s not that long. That same year, she also guest starred in Wizards of Waverly Place and fellow CBS series CSI, while starring in the films Pretty Ugly People and Seven Pounds.
Danica McKellar
Danica McKellar guest starred in Season 3, Episode 12, “The Psychic Vortex” in 2010. She plays Abby, a Caltech grad student who meets Sheldon and Raj at a University Mixer. Abby and Raj go on a double date with her friend Martha and Sheldon, and even though they later make out with each other, Abby doesn’t come back.
Courtney Ford
Courtney Ford appeared as Alice in Season 5, Episode 7, “The Good Guy Fluctuation.” Leonard meets her at the comic book store and like him, is also a comic books enthusiast. She draws her own comic books and takes a liking to Leonard. They bond over comic books, and the guys wonder how he managed to land her. All seems to go well with them until Leonard tells her that he has a girlfriend, and they part ways, not very amicably.
Josh Peck
Seven years after starring as Josh Nichols on Drake & Josh, Josh Peck appeared on The Big Bang Theory as Jesse in Season 7, Episode 13, “The Occupation Recalibration.” Jesse is the owner of Capital Comics Store, a rival of Stuart’s Comic Center. They are in a feud, but it’s short-lived. In the episode, Bernadette and Stuart buy a comic for Howard, and Jesse is pretty sleazy with both of them, but he certainly made an impression.
