Sienna Miller is All Smiles Arriving at Dinner in London

Sienna Miller flashes a huge smile as she arrives with Hayley Squires at the Groucho Club on Wednesday night (August 9) in London, England.

The 35-year-old actress went chic in a black outfit as she enjoyed a night out after performing in her new play Cat On a Hot Tin Roof.

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The following morning, Sienna was spotted chatting on the phone as she arrived at the Apollo Theatre to prepare for her show later that night.

The London production of Cat on a Hot Tin Roof is running through October 7.

Also pictured inside: Sienna Miller leaving her Thursday night (August 10) performance in jeans and a T-shirt.