Keira Knightley is a terrible secret-keeper

Keira Knightley is ''terrible'' at keeping secrets. While the 28-year-old beauty plays the love interest of a CIA agent in new film Jack Ryan: Shadow Recruit, she insists she could never be a covert operative herself because she would end up spilling all the classified information.

She said: ''I'm terrible at keeping secrets - it would come straight out of my mouth, so I'd be an awful CIA agent.''

Knightley will next be seen in a singing role in Can a Song Save Your Life?, which co-stars Maroon 5 hunk Adam Levine - who was recently voted Sexiest Man Alive - but the British starlet says the singer didn't help her find her voice on set and left her to her own devices.

Asked if Levine gave her tips, she said: ''No, he didn't, actually! He's one of those annoying singers that just kind of thinks everyone can sing, kind of like, 'I don't know ... just do it!' ''

Like his co-star, Jack Ryan leading man Chris Pine will also serenade audiences in Disney's new fairytale-themed musical movie 'Into the Woods', but the 33-year-old stud isn't convinced his vocals are entirely up to scratch.

Pine says he took singing lessons ''for months'' to prepare for the role of Prince Charming, but his co-stars weren't overly complimentary of his efforts.

Speaking at the European premiere of Jack Ryan in London's Leicester Square on Monday, he told BANG Showbiz: ''I got kind of, like, vague, casual smiles - nothing too effusive!''