Gerard Butler and Jennifer Aniston. (WENN.COM)

Scottish actor Gerard Butler enlisted the help of his Bounty Hunter co-star Jennifer Aniston to play a cruel prank on his mother - by pretending they had eloped.

The pair sparked rumours of a romance after sharing the screen in the new comedy and jetting off on holiday to Mexico to celebrate Aniston's recent 41st birthday.

Both stars have denied they are in a relationship, but Butler used the press stories to fool his mother into thinking he had proposed to the former Friends actress.

He explains, "I took the phone and said, 'Hey mum, I'm a little busy right now, I'm marrying Jennifer Aniston.' Jen took the phone and had a conversation with my mum and introduced herself as my mum's daughter-in-law. My mum was so excited. She's desperate for me to get married."