Sienna Miller stood in for the leading lady in Thursday night's performance of As You Like It in London's West End, astounding cast and audience alike.
Actress Helen McCrory , who plays Rosalind in the William Shakespeare comedy, collapsed from gastro-enteritis and dehydration during a matinee performance.
But although director David Lan was set to enlist the services of understudy Denise Gough for the evening show, he received a text message from Miller saying: "I know Rosalind's part if you need me to do it."
And the star - who has been panned by theatre critics for her "wooden" performance in her usual supporting role as Celia - saved the day with just 90 minutes before the curtain rose.
Lan says, "I was astonished. There was absolutely no reason why Sienna should know a single line."
Miller said afterwards, "I'm not completely conscious of what just happened. I've felt in a complete state of shock and in a way I still am. I just attempted to imitate Helen McCrory."