British beauty Kate Beckinsale has laughed off reports she has been having an affair with a male friend behind her husband Len Wiseman's back.

The Aviator actress has been happily married to Wiseman for 19 months after falling in love on the set of the first Underworld movie in 2003.

Despite recent rumours their marriage was on the rocks, Beckinsale insists they are as happy as ever.

Beckinsale explains, "There's a made-up story where I'm supposed to have gone rushing off to England for a secret tryst with a male friend.

"Well it's actually my friend's husband and they've just had a baby. Supposedly I took advantage of the swollen ankles and moved in for the kill.

"We have a good giggle about that one. I keep sending my friend emails saying, 'But your husband is a fantastic shag, isn't he?'"