She’s currently treading the boards in the West End in Cat On The Tin Roof.
And Sienna Miller opted for an unusually casual ensemble as she left the Apollo Theatre in London following another successful performance on Wednesday night.
The 35-year-old dressed down in a grey T-shirt and red tracksuit bottoms as she made her way out of the stage door.
Casual chic: Sienna Miller dressed down in red tracksuit bottoms as she left the Apollo Theatre in London on Wednesday night following another performance in Cat On The Tin Roof
The stylish actress made sure to stay on trend with a pair of Gucci trainers to add to the sporty look.
Harking back to her boho days, the star accessorised her ensemble with a tan satchel slung over her shoulder.
Wearing her blonde tresses down in waves, Sienna showed off her glowing complexion with a natural make-up look, accentuating her eyes with a liberal coating of mascara.
Sienna is currently starring in Tennessee Williams’ play Cat On The Tin Roof, alongside Skins actor Jack O’Connell.
Natural: The actress, 35, appeared to be in high spirits following her starring role in the Tennessee Williams play
She has received rave reviews for her performance as Maggie in the drama, which runs until October 7.
The Benedict Andrews’ directed play centres around the sexual tension between her character and her alcoholic husband Brick, who some believe is in denial about his homosexuality.
Sienna sparked false engagement rumours earlier this month after accidentally leaving a a piece of costume jewellery on while leaving the theatre.
Sporty vibe: The Hollywood star opted for a casual look, teaming her bottoms with a simple grey T-shirt and a pair of stylish Gucci trainers
Chic: Harking back to her boho days, the star accessorised her ensemble with a tan satchel slung over her shoulder
Starring role: Sienna has received rave reviews for her performance as Maggie in the play
The sizeable ring set tongues wagging about potential wedding bells for her and her director boyfriend, Bennett Miller, 50, who she met on the set of the 2014 film Foxcatcher.
However, a source close to Sienna later dismissed the claims as a ‘silly mistake’ and said there was no engagement.
Sienna shares daughter Marlowe, five with her former fiancé Tom Sturridge, whom she dated from 2011 to 2015.
She’s a natural: Wearing her blonde tresses down in waves, Sienna showed off her glowing complexion with a minimal make-up look
Leading lady: The British actress stars alongside Skins actor Jack O’Connell in the play