The 38-year-old "Vicky Cristina Barcelona" star will be photographed wearing the 2012 Key To The Cure T-shirt, which will be sold in Saks Fifth Avenue stores this autumn to raise money for the Women's Cancer Research Fund, reported Contactmusic.
The fund benefits charities aiming to find innovative detection methods, better treatments and eventual cures for cancer.
"I am honoured to join the Entertainment Industry Foundation's Women's Cancer Research Fund and Saks Fifth Avenue to raise awareness for women's cancers. Cancer has affected each and every one of us in one way or another and I am thrilled to be involved with this wonderful cause," Cruz said.
Previous ambassadors for the annual initiative include Hollywood beauties Gwyneth Paltrow and Uma Thurman.