Karen Miller and Seth RogenDuring actor Seth Rogen's appearance on 'The Tonight Show,' he described to host Jay Leno how he popped the question to fiancee Lauren Miller.

Men planning to propose to their girlfriends, listen carefully to Rogen's words for a cautionary tale. His story is a lesson in how not to propose to the woman you love.

For fear of losing the ring, Rogen scrapped his elaborate proposal plans and ran upstairs to pop the question to his lovely girlfriend right away.

"She happened to only be in her underpants," he said, noting specifically that her upper body was bare.

"I didn't think I'd be telling it so much when I did it," Rogen lamented. "Her parents have heard me tell the story, and her dad's not happy about it." Watch the video after the jump.