Keira and Sienna are beachy keen on each other

Sienna Miller and Keira Knightley are preparing to shoot an onscreen lesbian scene, but off screen, the pair are more interested in tomfoolery.

Taking time out between takes of romantic drama The Best Time of Our Lives, the Hollywood stars frolicked along the Wales beachside and giggled like schoolgirls.

Keira says she wishes she could be more like her co-star Sienna Miller

The stars are teaming up with actor Matthew Rhys for a steamy threesome scene - Rhys plays Welsh poet Dylan Thomas, who has two women competing for his love.

Miller, who plays Thomas' wife, stepped into the role after troubled actress Lindsay Lohan pulled out over monetary negotiations.

Knightley has spoken of her real life affection and admiration for her co-star.