Cara Delevingne wore a white bridesmaid dress by Chanel to Poppy Delevingne's wedding to James Cook on May 16 in London Credit: Neil P. Mockford/GC Images

Pulling a Pippa? Cara Delevingne cut a stunning figure in her bridesmaid dress at sister Poppy Delevingne's wedding to James Cook on Friday, May 16. 

Like fellow Brit Pippa Middleton at older sister Kate Middleton's 2011 wedding to Prince William, Cara matched the bride in a gorgeous white gown. The feminine frock, by Chanel Haute Couture, featured fluttery sleeves and a semi-open back, which she showed off by putting her long hair up into a bun.

Poppy, meanwhile, was a vision in her own textured Chanel Haute Couture dress, which had a sheer skirt and embroidered flower embellishments. (Blake Lively rocked a similar Chanel gown at the L.A. premiere of Green Lantern in 2012.) She wore her blonde hair in waves, and pinned a veil to the back of her head.

Cara, 21, tweeted about the wedding shortly before her older sister's walk down the aisle, sharing a picture of the happy couple's invitation on Instagram. "The big day," she wrote alongside the photo.

Poppy, 27, first got engaged to Cook back in October 2012. "It all feels pretty surreal at the moment, but I'm truly over the moon," the model told Vogue U.K. at the time. "Even though we've been going out for almost five years, the proposal was such a surprise, I practically fell off my chair," she gushed. "Dress-wise, I get butterflies just thinking about it, but I guess we'll just have to wait and see."