text: Forget friendly competition – it seems that real friends in the fashion world will do all they can in order to help promote each other, including starring in a campaign for a competing label. Versace designer Donatella Versace, 59, is set to appear in a new ad campaign not for her own brand, but for rival design house Givenchy. Givenchy designer Riccardo Tisci, 40, revealed the surprising pick for his fall-winter campaign on Instagram yesterday, posting a black and white photo of himself and Donatella, who he described as his ‘ultimate icon’. Double the designer power: Versace designer Donatella Versace appears in a photo with Riccardo Tisci for Givenchy's new ad campaign . 'So proud and honored to introduce my new ultimate icon: Donatella Versace... FW15 Givenchy Family Campaign [sic],' he wrote, while promising that more images from the campaign will be unveiled soon. Donatella re-posted the snap on her own account, captioning it: 'For my talented friend Riccardo. Together we break fashion boundaries today!' 'You made my day unforgettable,' she continued in another post, thanking Riccardo and the shoot's photographers, Mert Alas and Marcus Piggott. Fashionable friends: Donatella, left, and Riccardo, second from left, are longtime friends; they are pictured here with Franca Sozzani, second from right, and Naomi Campbell, right . Big name in the business: Donatella regularly appears in ads for her own design house, Versace, but this is the first time she is modeling for another designer. Casting Donatella in the campaign is without a doubt an unusual choice - both high-fashion brands attract similar clientele, including celebrities like Kim Kardashian and Zoe Saldana - but the designers have actually been friends for years, since first meeting at a Vogue Italia dinner a decade ago. In fact, Donatella interviewed Riccardo for Interview Magazine in 2011, telling him she found his most recent collection at the time to be 'very beautiful - super sexy' before adding that she would 'wear all of it'. That didn't surprise Riccardo, as the designer explained that he was 'obsessed' with Versace as a child and is still inspired by the brand's designs. 'Donatella, you are so much of a Givenchy woman!' he told her. 'I would really love to see you dressed in Givenchy.' Backstage BFFs: Riccardo posted this photo of himself with Donatella during Paris Haute Couture Week . Both Givenchy and Versace have many celebrity fans; Donatella is pictured here with Versace lovers Kate Hudson, left, and Goldie Hawn, right, at Paris Fashion Week this year . Riccardo has more recently proved that he is a fan of Donatella's work as well. At Paris Haute Couture Week earlier this year, the Givenchy designer posted a picture of the pair together backstage and referred to Donatella as a 'couture queen' in the photo's caption. Now, Donatella is returning the complement by lending her face to his Givenchy ads. 'You are one of the most talented designers there,' she told him in 2011. 'What you and I have in common, Donatella, [is] that careful balance,' he said, referring to their joint ability to push boundaries without becoming vulgar. Now the pair will have Givenchy's fall-winter campaign in common too.
target: Givenchy designer Riccardo Tisci, 40, announced that Donatella, 59, will appear in his new ad campaign .
  The top designers work for competing fashion brands, but they are good friends in real life .
  Riccardo once told Donatella he would love to see her dressed in Givenchy .