Keira Knightley almost turned down a part in ‘Pirates of the Caribbean’.

The actress - who is on a worldwide tour promoting the sequel, ‘Dead Man’s Chest’, to the 2003 hit - says the fact the film was based on a theme park ride put her off.

She said: “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 star - who was nominated for an Oscar this year for her role as Elizabeth Bennet in ‘Pride and Prejudice’ - was also convinced the original film was going to be rubbish.

She revealed to America’s New York Daily News newspaper: “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 theatre all smiles.

“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.”

The first movie, ‘Pirates of the Caribbean: The Curse of the Black Pearl’, eventually made $650 million worldwide.

The second film opens this month, while a third instalment - tentatively titled ‘Worlds End’ - is due for release next year.