Sienna Miller has thanked theatre audiences who gave her a standing ovation on the day she discovered her then fiance Jude Law's infidelity, insisting their support carried her through.

The actress called off her engagement in July (05), after learning Law had an affair with his children's former nanny DAISY WRIGHT. Despite her heartache, the 24-year-old star valiantly vowed not to disappoint fans who had tickets to see her play CELIA in William Shakespeare's AS YOU LIKE IT at London's Wyndham's Theatre.

She says, "I don't know how I did it. I was vomiting in the wings. That was really tough. Knowing that 800 people in front of you know exactly what you are going through made it tough.

"The first night I was just a wreck and then afterwards all these women stood up and were like, 'Go girl!'

"They were like sisters and very supportive, but it was a little weird feeling all these people willing you through it.

"There were all these bits in the play where I had to cry and I could just hear themselves asking, 'Is she really crying?'"