Joan Collins and Johnny Galecki in The Late Late Show with James Corden (2015)

Kathy Bates, Kaley Cuoco, Johnny Galecki, and Teller in The Big Bang Theory (2007)

Johnny Galecki and Teller in The Big Bang Theory (2007)

Mayim Bialik, Kaley Cuoco, Johnny Galecki, Simon Helberg, Jim Parsons, Melissa Rauch, and Kunal Nayyar in The Big Bang Theory (2007)

Justin Timberlake and Johnny Galecki in In Time (2011)

Justin Timberlake, Johnny Galecki, and Will Harris in In Time (2011)

Faith Ford and Johnny Galecki in Hope & Faith (2003)

Sara Gilbert and Johnny Galecki in Roseanne (1988)

Kaley Cuoco, Johnny Galecki, and Kunal Nayyar in The Big Bang Theory (2007)

Neil Gaiman, Johnny Galecki, Simon Helberg, Kevin Sussman, and Jim Parsons in The Big Bang Theory (2007)

Peter MacNicol, Johnny Galecki, Simon Helberg, Jim Parsons, and Kunal Nayyar in The Big Bang Theory (2007)

Kaley Cuoco, Johnny Galecki, and Parvesh Cheena in The Big Bang Theory (2007)

Kaley Cuoco, Johnny Galecki, and Bob Stephenson in The Big Bang Theory (2007)

Johnny Galecki and Bill Gates in The Big Bang Theory (2007)

Mayim Bialik, Johnny Galecki, Simon Helberg, and Eric Normington in The Big Bang Theory (2007)

Johnny Galecki and Aaron Takahashi in The Big Bang Theory (2007)

Mayim Bialik, Stephen Colbert, Kaley Cuoco, Johnny Galecki, Simon Helberg, Jim Parsons, Melissa Rauch, and Kunal Nayyar in Johnny Galecki/Jim Parsons/Kaley Cuoco/Simon Helberg/Kunal Nayyar/Mayim Bialik/Melissa Rauch/Barenaked Ladies (2019)

Christine Baranski and Johnny Galecki in The Big Bang Theory (2007)

Johnny Galecki in The Big Bang Theory (2007)

Mayim Bialik, Kaley Cuoco, Johnny Galecki, and Jim Parsons in The Big Bang Theory (2007)

Johnny Galecki and Kunal Nayyar in The Big Bang Theory (2007)

Kaley Cuoco and Johnny Galecki in The Big Bang Theory (2007)

Johnny Galecki and Jim Parsons in The Big Bang Theory (2007)

Christopher Walken, Sean Patrick Flanery, Jay Mohr, Henry Thomas, Jeremy Sisto, and Johnny Galecki in Suicide Kings (1997)

Christina Ricci, Lisa Kudrow, Ivan Sergei, Lyle Lovett, and Johnny Galecki in The Opposite of Sex (1998)

Rachael Leigh Cook, Lukas Haas, Nick Stahl, and Johnny Galecki in Bookies (2003)