The Nashville star admits she can't get to sleep if her room is blacked out.

"I'm terrified," she says. "I fall asleep with my TV on. I hate it."

She faced her fears during a recent appearance on singer Harry Connick, Jr.'s U.S. talk show, when he handed her a flashlight and dimmed his studio lights.

As it got darker and darker, Hayden began to get a little nervous and told the host, "I don't want to", when he said, "We have to go all the way".

She started squealing as the lights went out completely and turned on her torch.

The two stars ended their interview in the darkness of the studio and the actress sighed with relief as the lights came back on when the show went to a commercial break.