"For as long as I can remember, Guess has been at the epicentre of fashion for women. I am honoured to be face of the brand and this iconic holiday campaign," Priyanka said in a statement.
"Guess is aspirational, inspirational and so relatable to women from across the world," added the actress, who is carving a niche for herself as a singer on the global arena. Her first single was "In My City".
The star of films like "Dostana", "Fashion" and "Barfi!" feels the association will help her "erase boundaries" and "make the world a smaller place".
Paul Marciano, creative director of Guess, says the actress is the ideal choice for the brand.
"Priyanka's confidence, strength and sensuality reflect the qualities I always look for in a model. She reminds me of Sophia Loren and the top actresses of the 1950s," said Marciano.
He added: "With the Indian movie industry exploding on a global stage, and Guess having a brand presence in 87 countries, we could not have found a better global brand ambassador. Choosing Priyanka reinforces our celebration of multi-talented, dynamic and accomplished women."