Balmain's sister act

Olivier Rousteing has long proclaimed the strength of the Balmain nation, but it appears there's one thing stronger: the Balmain family.

For the label's Fall 2015 campaign, photographer Mario Sorrenti captured three sister acts: Kendall and Kylie Jenner, Bella and Gigi Hadid, and Joan and Erika Smalls.

While the former are all naturals in front of the lens, the campaign marked a first for Erika Smalls, a self-described 'social entrepreneur'.

Having made a cameo in a 2012 US Vogue feature on her model sister Joan, the two share the spotlight in the Balmain campaign.

Of her appearance for Balmain, Erika said: "It was a pleasure and memorable experience working with everyone on set! I am deeply grateful for this opportunity."

The notion that inspired the campaign was a heartfelt one from Rousteing, who was, "Struck by the love and emotion," he witnessed between Kim Kardashian West and Kanye West while working with them on Balmain's Spring 2015 advertising campaign.

"With a determination to once again focus on the beauty of an intimate connection, my team and I quickly concluded that a celebration of the unique and unconditional love of siblings is a natural progression from the spirit of last season," he went on to say.

Continuing the family ties, brothers and models Armando and Fernando Cabral appear in the Fall 2015 Menswear campaign, having previously been cast together in H&M's Holiday 2010 campaign.