Actress Keira Knightley is petrified of being outshone by new, younger stars and feels she may have passed her prime, despite being only 20.

The Domino actress shot to stardom at 14 when she played SABE in STAR WARS EPISODE I: THE PHANTOM MENACE and has since starred in a number of high-profile films including Pirates Of The Caribbean and Pride And Prejudice.

Despite her superstar status, the pretty brunette fears the height of her film career may be coming to an end.

She says, "One magazine called another young actress 'The next Keira Knightly' and I'm thinking, 'Hold on, am I past my prime already? I'm only 20 years old'."