Katie Couric falls down Corden's stairs

This was a pretty good way to close out April Fools' Day.

Guests entering James Corden's Late Late Show walk down a set of stairs. But Katie Couric was fixing her shoe as she took her first step and immediately took a tumble right down as she made her appearance Wednesday night.

Over and over she went.

Corden jumped up from behind his desk. The band stopped playing. The audience was stunned.

"April Fools!" Couric shouted, standing at the top of the stairs. Yes, she had a stunt double doing her dirty work.

"I can't breathe. That's like our worst nightmare," said a seemingly surprised Corden. "We've been talking about those stairs. We've been going back and forth. I was like, 'Oh, my God. Katie Couric just died.' "