British actress Keira Knightley poses at the world premiere of her new adventure film 'Pirates of the Caribbean: Dead Man's Chest' at Disneyland in Anaheim, California, June 24, 2006. Knightley stars as 'Elizabeth Swann' in the film which opens in the U.S. July 7. REUTERS/Fred Prouser (UNITED STATES)

Keira Knightley acknowledges she was a bit skeptical at first about appearing in a movie that shared a name with a Disney ride.

"I was like, 'Wait a minute, you're doing a pirate movie - something that hasn't worked in about 50 years - and it's based on an amusement park ride?!" the actress told the New York Daily News for a story published Sunday.

The 2003 film "Pirates of the Caribbean: The Curse of the Black Pearl" went on to be a $650 million worldwide success, and co-star Johnny Depp earned an Oscar nomination for his role.

Knightley appears again in the sequel "Pirates of the Caribbean: Dead Man's Chest," opening Friday. A third "Pirates" installment is due out Memorial Day weekend next year.

Knightley says it wasn't until she was at the premiere of the first "Pirates" movie with co-star Orlando Bloom that she knew the premise would work.

"Orlando and I were sitting next to each other at the premiere, which was the first time I'd seen it, and we'd had a big talk and decided that if it was awful, we'd still leave the theater all smiles," she said.

"Halfway through the film, I nudged him and said, 'It's quite good, isn't it?' and he was like 'Yeah, it's really good.' We had no idea it would work."