Fears for troubled Sienna

There were concerns over the health of Sienna Miller last night after she was seen with a series of cuts on her arm.

The five parallel red marks were visible across the actress's left forearm as she left the stage door after her performance in As You Like It at Wyndham's Theatre in the West End late on Monday evening.

Miss Miller - who sobbed last week as she reportedly ended her relationship with movie star Jude Law over his infidelity - was photographed walking to the fashionable J Sheekey fish restaurant, where she met a friend for a late supper.

She had come from a question-and-answer session following her stage performance, where fans quizzed her and the rest of the cast about the Shakespeare play.

During the session, the 23-year-old star appeared taken aback when asked if she found it difficult to act amid recent revelations that Law had had an affair with Daisy Wright, the nanny of his children. 'Not at all,' she said.

She added that she saw the theatre as a kind of therapy. 'There's this lovely expression - Dr Theatre. It's great. It's what I love doing. I wouldn't want to do anything else.' During the halfhour session, Miss Miller - who chain-smoked cigarettes - said the cast had been very supportive towards her. She also claimed, with a hint of sarcasm, that they 'never drank' after the shows.

A friend of Miss Miller said last night that she remains 'devastated' by the public humiliation of Law's infidelity.

'She is still finding it hard to cope,' the friend added. 'She is trying to put all this behind her and has thrown herself into work, which really is helping. But in the quiet times, when she's on her own, reality comes crashing down and there are still a lot of tears.'

Last night, Miss Miller's publicist Ciara Parkes said the marks on her arm were due simply to a bizarre swimming accident at the weekend, when waves washed her into a rocky outcrop at the English seaside. Law, 32, gave a grovelling public apology to the actress following an account by Miss Wright of the month-long affair she had with him when she joined him on a film set in New Orleans.

After the revelations, Miss Miller's mother, Josephine, said of Law: 'It's a terrible thing he did. We feel so betrayed by him, he's so stupid. He's a bloody idiot, in fact.

'It's such a disgusting thing to do and we were all shocked when we found out.' Miss Miller has tried to put the star's infidelity behind her and

was seen with her ex-lover Orlando Bloom and Prince Harry at an international polo match in Windsor.

Law took a week's break at his parents' home in France after his affair was exposed. He reportedly spent much of that time on the phone to Miss Miller, begging her to take him back. According to friends of the couple, they are still trying to work things out.