The `Atonement` actress and actor Rupert Friend decided to call time on their five-year romance just after Christmas and although they are both devastated, the decision to break up was mutual.
Keira`s father Will Knightley told The Sun newspaper: "Yes, they have broken up. But that`s the way things go, unfortunately. I`ve spoken to her recently. The only option is to get on with things.
"They were together for quite a long time and it is always hard breaking up. She`s focused on her work."
Keira, 25, met 29-year-old Rupert on the set of 2005 movie `Pride and Prejudice` but sources claim Rupert started to find it difficult as his girlfriend became more famous and successful.
A friend said: "Rupert hates the idea of being followed or photographed. Keira partially had to accept it because of her rising profile.
"It affected the harmony in the relationship. The pressure on such private people took its toll and both decided they should go their separate ways. They will remain life-long friends."
In 2009, Keira hinted her relationship with Rupert was on the rocks as she starred in the West End show `The Misanthrope` where she portrayed 22-year-old movie star Jennifer.
Speaking of the character, she said: "Do I recognise being an extremely well-known young actress? Yes. And she`s in the middle of a world full of people who are quite a bit older than her. She`s having a problem with her boyfriend. No comment."