The `Vow` actress - who has been in a relationship with Michael Sheen for 18 months - feels "tenderness" towards her former partners, which include Ryan Gosling and Josh Lucas, because of the things they have taught her.

She said: "Am I still friends with my old boyfriends? Yes, absolutely. There`s no one who`s ever been significantly in my life for whom I don`t have a sort of tenderness because they helped to shape who I am.

"However long someone is in your life, they`re there to teach us something and I try to make the most of any relationship."

The 33-year-old beauty values humour most in a boyfriend and she thinks it is particularly important to be able to laugh at problems.

She added to Britain`s HELLO! magazine: "First and foremost, a sense of humour [is attractive]. You can have passion, you can have interests in common and all the other good things. But if it`s to be a long-term relationship, then you`re going to need something to get you through the trials and tribulations.

"The ability to laugh together and not take anything too seriously is essential. It`s a way to connect that forgives a lot of other things and it allows you to move on much more quickly if there`s a problem."
sections: Celebrities