They say that once you've learned to ride a bike, you never forget.

But it looks as if Sienna Miller could do with a helping hand as she struggles to keep steady on two wheels.

The 25-year-old actress even appeared to come a cropper and ended up with a nasty cut on her forehead.

So far so good for Sienna as she films a scene for 'The Edge of Love'

Ouch! Sienna runs into trouble...and they say once you learn to ride a bike you never forget

Fortunately, it was all in the line of work. Sienna was filming a scene for her latest movie and her painful-looking injury was simply make-up. And any particularly risky activity on the bike was performed by a stunt double.

Sienna was pictured in New Quay, West Wales, where work is under way on The Edge Of Love.

The movie is about a love triangle in the life of Dylan Thomas. Matthew Rhys plays the Welsh poet, Sienna is his wife Caitlin and Keira Knightley plays Thomas's childhood friend Vera Killick. The film is due to be released next year.

Sienna with an 'injury'

During filming, Sienna's blonde locks have been turned red and she has ditched her usual bohemian look for a more traditional Forties style.

Wearing a light blue, knee-length dress, a light grey woolly cardigan and sensible pump-style shoes, the actress looked every inch the wartime housewife.

But the look is not likely to be one the actress intends to promote with the launch of her new clothing line in September.

Sienna is following in the footsteps of Kate Moss, Lily Allen, Madonna and Kylie Minogue by making her mark on the world of fashion. She is teaming up with her sister Savannah to launch their own fashion line, called Twenty8Twelve.