Keira Knightley wanted to star in 'Jack Ryan' because she's ''always loved thrillers''.

The 'Pirates of the Caribbean' actress is a massive fan of the genre and was desperate to play the titular character's wife Cathy in the big screen adaptation of Tom Clancy's book series, a role she beat off competition from Evangeline Lilly, Felicity Jones, Kate Beckinsale and Jessica Biel to land.

She told Collider.com: ''I've always loved thrillers. Thrillers are incredibly difficult to do which is why there's so few of them made now, and [the 'Jack Ryan' films] have always been really good thrillers, so I sort of fancied that.''

Since starring in 'Pirates of the Caribbean: At World's End' - the third film in the franchise - in 2007, the 27-year-old actress hasn't had any hugely action packed roles and admitted that she's in the mood for a ''Hollywood sort of run-around with explosions'' project.

Keira was even more excited to star in the movie alongside Kenneth Branagh, who is also helming the motion picture.

She added: ''I'm working with Kenneth Branagh who has been a hero of mine since I was about six or seven.

''Getting to be directed by him and act with him is something that I just thought, 'I want to do that.' ''

The film - which sees 'Star Trek' actor Chris Pine take on the lead role - will follow the titular character as he discovers a Russian plot to destroy the US economy with a terrorist attack.

'Jack Ryan' will be released in the UK on December 26, 2013.