Actress Keira Knightley needed a break from all her "dark" film roles so she signed up to star in a comedy "Seeking a Friend for the End of the World".

The 26-year-old has done a series of dramatic roles since her breakthrough in the "Pirates of the Caribbean" franchise, and now she wanted to show off her playful side with a bit of light relief.

"I did do a comedy over the summer, because I thought, 'Jesus, this is just going from dark to darker to darkest, I need to lighten up a bit," quoted Knightley as saying.

"I told a friend, 'Don't worry, it's much lighter,' and then when she asked me what it's about, I had to say, well, the end of the world! Maybe the apocalypse is as light as I can go right now," she added.