Cressida Bonas supported her half-sister Isabella Branson's latest acting venture on Wednesday night.
The 25-year-old was joined by her extended family at The Tricycle Theatre in London to see 34-year-old Isabella perform in The Colby Sisters Of Pittsburgh, Pennsylvania.
Cressida and Isabella's mother Lady Mary Gaye Curzon was also in attendance as were Isabella's husband Sam Branson and her mother-in-law Joan Templeman.
Fresh from the stage, Isabella joined her relations at the show's after party to celebrate.
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The model and actress, who previously starred alongside Kristen Dunst and Simon Pegg in How to Lose Friends and Alienate People, sported a summery sleeveless jumpsuit for the occasion.
Cressida, who recently made her own acting debut at the Hay Festival in Wales, wore a simple black dress, metallic gladiator sandals and a denim jacket.
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The socialite held her blonde locks in place with a black headband and accessorised her outfit with gold hoops earrings and numerous rings.