Keira Knightley is going to make her fiancé James Righton write a love song for her.

The couple have been together for two years but the Klaxons singer is yet to pen a track in which he proclaims his love for the actress, and Keira insists that will soon change.

She said: ''I don't know if James ever wrote a song for me, but now that I think about it, I'll have to force him to do so! He should.''

The 27-year-old screen beauty got engaged to James, 29, in May 2012 and although she is excited about tying the knot and has been busy planning their big day, Keira admits she never thought she would ever walk down the aisle.

Keira - whose mother is playwright Sharman Macdonald and father is theatre actor Will Knightley - told IO Donna magazine: ''I had never even thought I would get married, my parents, though, have been together for 40 years and I know many people who have been in very long relationships. I don't know what to expect from my marriage, I guess it's just one of those things you have to wait to find out...''