Keira Knightley and Sir Elton John back International Women's Day

Keira Knightley, Sir Elton John and Naomie Harris are among the stars who have signed an open letter calling for an end to violence against females as part of International Women's Day on Friday (08Mar13)

The stars have joined a group of high-profile celebrities in putting their names to a note, published in Britain's The Guardian newspaper, supporting the global initiative to highlight the struggle of women across the world.

Singers Annie Lennox and Emeli Sande, funnyman Eddie Izzard, actors Dominic Cooper and David Oyelowo, and Hollywood couple Sam and Aaron Taylor-Johnson have also signed the letter.

A number of other stars have backed the cause by highlighting International Women's Day in posts on Twitter.com.

Maroon 5 frontman Adam Levine, pop group The Wanted and rockers Paramore have all tweeted messages of support.