'The Big Bang Theory's' Nerdiest Guest Stars

9:30 AM 9/26/2016

by Lesley Goldberg

From comic book legend Stan Lee to a plethora of 'Star Trek' alums the CBS comedy has had its fair share of geek gods pop by.

Christine Baranski

Christine Baranski earned two Emmy nominations for guest actress in a comedy for playing Leonard's psychiatrist/neuroscientist -- aka Sheldon's perfect woman (that is, before Amy). She has appeared multiple times on the CBS hit, including via Skype.

PHOTOS: Behind the Scenes: 'The Big Bang Theory'


CBS' The Big Bang Theory has featured a long list of amazing guest stars — from real-life astronauts to the king of comics, Stan Lee, and everyone in between. Here, THR takes a look at the nerdiest (and greatest) of them all.

  • Bob Newhart

    TV legend Bob Newhart guest starred as Professor Proton, the former host of Sheldon's (Jim Parsons) favorite science show. As it turns out, the science guru also happened to be a key player in the childhoods of both Sheldon and Leonard (Johnny Galecki). Newhart earned an Emmy for the role. The series ultimately killed off the character — but he continues to appear to Sheldon via a storyline ripped from Star Wars.

  • Buzz Aldrin

    Buzz Aldrin, the second man to walk on the moon, guest starred during season six, playing (naturally) an astronaut who enjoys sharing his accomplishments with anyone who will listen -- including children on Halloween. Raj (Kunal Nayyar) shows newly returned astronaut Howard (Simon Helberg) a clip of Aldrin with the hope that his best friend might talk about his own trip to space a bit less.

  • Christine Baranski

    Christine Baranski earned four Emmy nominations for guest actress in a comedy for playing Leonard's psychiatrist/neuroscientist — aka Sheldon's perfect woman (that is, before Amy). She has appeared multiple times on the CBS hit, including via Skype.

  • George Takei

    Star Trek's George Takei played himself in Howard's dream sequence — which also featured Battlestar Glactica's Katee Sackhoff. The dream helps Howard realize he still has feelings for his future bride, Bernadette (Melissa Rauch).

  • Kate Micucci

    Kate Micucci of musical comedy duo Garfunkel & Oates (and Raising Hope) played Raj's first real love interest, Lucy, during season six. Despite both of their social hang-ups, the duo shared a sweet date at a library — during which they communicated via text message.

  • Katee Sackhoff

    Katee Sackhoff played one of the many women of Howard's dreams. During her first appearance (in season three), the duo shared an intimate bath — in the reformed horn dog's dream, naturally.

  • Leonard Nimoy

    In keeping with Big Bang Theory's penchant for exploring the dream state, Star Trek's Leonard Nimoy guest starred with a voice role when a Spock action figure helped Sheldon deal with the guilt over breaking a valuable toy given to Leonard. 

  • LeVar Burton

    LeVar Burton has guest starred twice (so far), most recently returning for a special Star Trek-themed episode of web series "Sheldon Cooper Presents: Fun With Flags." 

  • Mike Massimino

    NASA astronaut Mike Massimino, right, played himself in a recurring role when Howard — aka "Fruit Loops" — journeyed to the great beyond. Massimino — a veteran of two space shuttle missions to service the Hubble Space Telescope — says that he was a fan of the show before booking the cameo gig and notes that Howard's cleverness would make him a "great person to fly with in space."

  • Sara Gilbert

    Sara Gilbert has appeared multiple times as Leslie Winkle, a fellow physicist at the university where Leonard, Sheldon, Howard and Raj work. While initially a love interest for Leonard, she eventually has a fling with Howard.

  • Stan Lee

    In an attempt to make up for missing Stan Lee's autograph signing, Penny (Kaley Cuoco) takes Sheldon to the comic book legend's house — uninvited. He ultimately winds up with an autograph — on a restraining order.

  • Stephen Hawking

    Sheldon's meeting with Stephen Hawking almost didn't happen after the uber-competitive geek spanked the theoretical physicist and cosmologist in a game of Words With Friends. "When people would ask us who a 'dream guest star' for the show would be, we would always joke and say Stephen Hawking — knowing that it was a long shot of astronomical proportions," executive producer Bill Prady said when the casting was announced. "In fact, we’re not exactly sure how we got him. It’s the kind of mystery that could only be understood by, say, a Stephen Hawking."

  • Steve Wozniak

    Apple's Steve Wozniak was quite impressed with the "virtual presence device" Sheldon created in an attempt to spare himself from the banalities of everyday socializing during a season four episode.

  • Summer Glau

    Terminator: The Sarah Connor Chronicles and Firefly alum Summer Glau had nowhere to run when the guys ran into one of their sci-fi favorites on a train ride to a Bay Area conference. While each attempted to hit on her, it was Howard who actually managed to get the (creepy) words out.  

  • Wil Wheaton

    Wil Wheaton has appeared multiple times playing a heightened version of himself (read: He's a tool!) as a longtime nemesis for Sheldon. Before the duo nearly came to (drunken) blows, Wheaton helped break up Leonard and Penny, costing Sheldon and Raj a game of Mystic Warlords of Ka'ah. Sheldon's meemaw would approve of their new friendship.

  • Laurie Metcalf

    Roseanne alum Laurie Metcalf plays Sheldon's religious mother from Texas, who in season nine took what could be described as a romantic interest in Leonard's father, played by Judd Hirsch. 

  • Judd Hirsch

    Taxi alum Judd Hirsch popped up as Leonard's father at the end of season nine and hit it off with Sheldon's mother — briefly leaving fans wondering if the CBS Chuck Lorre comedy would make Leonard and Sheldon brothers. 

  • Adam West

    Adam West guest starred as himself and popped in for an episode that celebrated Sheldon's birthday.

  • Bill Nye

    Bill Nye the Science Guy guest starred and played himself on The Big Bang Theory and played a rival to Bob Newhart's Professor Proton.

  • James Earl Jones

    James Earl Jones played himself in an episode in which he crosses paths with Sheldon, who as you'd expect of the character, freaked out at seeing the voice of Darth Vader. The two wound up hitting it off and spending the day together — ending with a game of ding dong ditch at Carrie Fisher's house.

  • Carrie Fisher

    So about that game of ding dong ditch? Yep, Carrie Fisher wound up popping in to surprise both Sheldon and James Earl Jones.

  • Keith Carradine

    Until season 10, Keith Carradine as Penny's father was the only member of her family viewers had seen on screen.

  • Katey Sagal

    Katey Sagal reunited with her former 8 Simple Rules on-screen daughter Kaley Cuoco on The Big Bang Theory to, yup, play her mother.

  • Jack MacBrayer

    The whole family gathered for Leonard and Penny's formal wedding in the season 10 premiere — including Penny's meth-head brother, Randall, played by Jack McBrayer.

  • Elon Musk

    The Tesla founder crossed paths with Howard while helping to feed the homeless on Thanksgiving. 

  • Adam Nimoy

    Leonard Nimoy's son, Adam Nimoy, guest starred as a documentary filmmaker and interviewed Sheldon for a doc on ... Star Trek.