Well-known movies that famous people were in when they weren't famous

[skp]

Haven't read all the replies but Nicholas Cage in Fast Times and Jeff Goldblum in Death Wish immediately come to mind. Maybe Goldblum is not so famous that most posters here would say "WTF, is that Jeff Golblum? Wow, I never realized HE was in that movie! But that's exactly what I said when I saw him in that flick.

Cage shows up at the grad party with Spicoli near the end of the movie. I don't even think he has any lines.

Goldblum is one of the guys who gang rape Chuck's wife at the start of the flick in Death Wish.

"Washington" of Welcome Back Kotter fame also has a two bit bad guy role in Death Wish but most posters here have probably never even heard of Welcome Back Kotter let alone the character named Washington.

Robert Urich (Dan Tanna in the TV show "Vegas") was in Magnum Force or some such Dirty Harry flick. He appears as a dirty cop along with David Soul ('Hutch' in Starsky and Hutch) Again, Dan Tanna and Paul Hutch are not exactly household names either. FWIW, David Soul is also a bit of a one hit wonder with a song called "Don't give up on us, baby". I digress.

Anyway, my pick overall would be Nicholas Cage.