The stunning actress is the Entertainment Industry Foundation's ambassador for this year's initiative and will appear in a national public service announcement wearing a limited-edition Carolina Herrera-designed T-shirt.
Shoppers will be able to buy the $35 shirt at Saks Fifth Avenue and Off 5th stores, as well as from saks.com with all proceeds benefiting EIF's Women's Cancer Research Fund and Penelope says she's thrilled to be involved.
She said: ''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.''
Carolina said her design, a map of the world covered with tiny hearts, is emblematic of the cause.
She told WWD: ''It is important to work all together because this disease goes everywhere in the world, and every family knows someone who has had a problem with it,. If we all get together to raise money for them, it works. If cancer is detected in the very early stages, it can be cured.''
Saks launched the campaign 14 years ago and more than $31 million has been raised for cancer research.