A ranking of the best ‘Big Bang Theory’ guest stars

Levar Burton on The Big Bang Theory

When The Big Bang Theory began airing on CBS in 2007, it only took three episodes for the first notable guest star to appear. A former Roseanne co-star of Johnny Galecki’s (who plays Leonard Hofstadter in the long-running comedy), Sara Gilbert played Dr. Leslie Winkle, a fellow scientist and a love interest for Leonard. She went on to become a recurring guest star along with well-known talents such as Laurie Metcalf, Christine Baranski, Judd Hirsch, and Wil Wheaton.

Ahead of the show’s finale, we ranked the top guest stars. Click here to read the full story and see where people like Stan Lee and Leonard Nimoy land on the list.