Amanda Seyfried admits the start of her relationship with Dominic Cooper was "messy".

The 'Jennifer's Body' actress met the British actor on the set of 'Mamma Mia!' in 2007 and while she knew there was a huge attraction between the pair she wasn't sure what would happen because he already had a long-term girlfriend, Joanna Carolan.

She said: "I fell for Dominic's sense of humour. He's just really, really funny and we fooled around so much during the rehearsals for 'Mamma Mia!' But it was messy because there was some overlap with his girlfriend who he'd been with for 12 years. I didn't know how he was going to deal with that, so we went our separate ways and I began dating someone else."

However, Dominic had decided to end his relationship and flew over to the US to win Amanda back.

She said: "Dominic flew over to Charleston, where I was filming 'Dear John', and he made sure I never saw that guy again."

Despite being extremely happy with Dominic, Amanda says she has no plans to marry him.

She told Britain's Glamour magazine: "As silly as it sounds, I've learned that you can't have expectations about a relationship. It's healthier that way. The things I worry about are the health of my family, where my career's going and my dog, Finn – but not relationship."