10 Huge Actors You Forgot Were In Scrubs

10. John Ritter

The late, great John Ritter was already a sitcom and movie royalty by the time he turned up in the first season of Scrubs. Known for his iconic roles in Three's Company and 8 Simple Rules, Ritter had appeared in dozens of TV shows before Scrubs and starred in over one-hundred films.

On the medical sitcom, Ritter played Sam Dorian, the unsuccessful but genuinely loving father of J.D. He carried with him an ease with inappropriate humour, was great friends with Turk, and was portrayed as an emotionally distant father who would nonetheless always come through for his kids.

Ritter only appeared in two episodes as J.D's father, because he tragically passed away not long after the episodes aired. The season four episode "My Cake" was made in tribute to the late actor, and as a farewell to the short-lived character he helped bring to life.