Jack Nicholson in Mars Attacks! Unmistakable as the president but pretty well disguised as the tycoon. I’d seen the film a few times and had even wondered who’d played the tycoon but I eventually came across a reference to him playing two parts. Had to watch again before I believed it.
Matt Damon in Mystic Pizza. “Mom, do you want my green stuff?”
I just found out today that Elinor Donahue, Betty from “Father Knows Best,” played Commisioner Nancy Hedford in the Star Trek episode “Metamorphosis.” Even after watching “Father Knows Best” reruns nearly every day, I never made the connection.
What’s even more embarrassing about it is my username. 