The announcement has come as little surprise to the industry, which has watched the 24-year-old's relationship with the veteran Italian designer go from strength to strength in recent years.
She is a regular at his catwalk shows, and wore an Armani Privé gown for her recent wedding to 90210 star Brian Austin Green.
In a statement today she said: Mr Armani is an iconic visionary for all things fashion.
'I’m honored to be associated with him and part of this campaign.'
And the praise from the designer was mutual. Armani called the actress 'confident and seductive.'
'She embodies the spirit of the women of today... Her beautiful features reveal femininity, sensuality and strength,' he said.
She is the latest in a line of high-profile actresses to front a beauty campaign for a major brand.
