Mark Hamill may be Luke Skywalker and the voice of the Joker, but once upon a time, he was a fast food worker — who got fired for doing voices.

Hamill opened up about his short-lived job at Jack and the Box on "The Late Late Show With James Corden." Fellow guest Bradley Whitford revealed he'd met Hamill when Whitford was an aspiring actor and waiter (and more importantly, that Hamill left a big tip.

Hamill, who voices Chucky in the new "Child's Play" movie opening June 21, then described his own short-lived fast food gig. 

"I was always trying to find the theatrical aspects of it," he explained. "I was in the back all the time, making shakes and manning the grill, and I always aspired to work the [drive-thru] window. The one chance I had at it — it never occurred to me to not be in character."

Hamill spoke to drive-thru customers in a high-pitched voice as the Jack in the Box clown.

"My manager didn't think it was very funny," Hamill said. "He told me to go home and never come back. I got fired. Fired! For being in character!"

Of course now Hamill is an acclaimed voice actor in demand from "Batman: The Animated" series and other projects. He will also reprise his most famous role in "Star Wars: The Rise of Skywalker" in December.

Hamill imagined telling that manager, "I'll show you! One day, I'll be The Joker and then you'll be sorry!"