Sienna Miller explains mystery scratches

British actress Sienna Miller is nursing a sore arm after injuring herself at the weekend.

The 23-year-old blonde sparked worries among her fans as she sported huge red scratches across her left arm as she left Wyndham's Theatre in London following her performance in 'As you like it' on Monday.

However, her spokeswoman claimed Miller has injured herself while swimming in the sea over the weekend, saying, "She grazed her arm and bruised her hip as she was buffetted against the rocks. She was laughing about it and hasn't suffered any long-term ill effects."

The former model is currently in discussions with estranged fiance Jude Law over the future of their relationship following last month's revelations he cheated on her with his children's nanny Daisy Wright.