Actress Sienna Miller has bowed out of Kevin Spacey's annual theatre extravaganza in London due to a scheduling conflict.

The "Factory Girl" star was due to participate in Spacey's 24 Hour Plays Celebrity Gala at the Old Vic theatre on Sunday but she has axed her appearance to film a movie.

Her spokesperson says, "Very sadly, she had to pull out due to a clash of dates and she's extremely disappointed not to be able to be involved."

Miller is believed to be in Los Angeles shooting the upcoming drama Yellow, in which she plays a drug addict.

Spacey's event will feature performers writing, directing and staging short plays in the space of one day.

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