The announcement follows Armani's decision to replace David Beckham as the new brand ambassador for Emporio Armani Underwear with Real Madrid footballer Christiano Ronaldo.
In a brief release Armani confirmed Fox's appointment and said photography for the campaign had been shot this weekend by Mert Alas and Marcus Piggott, who were also responsible for the Beckham ads.
Fox follows Victoria Beckham who was previously the female face of Emporio Armani Underwear. The first campaign with Fox is set for January, while Ronaldo's will launch in spring next year.
Armani's decision to bring in Fox follows recent speculation that the brand it was in talks with Angelina Jolie.
It was reported that Beckham refused to talk part in similar ads with the actress to those shot with wife Victoria Beckham "because he was married".
The Beckhams' association with Armani appears to be coming to a close, with .