Paltrow won an Oscar for her work in "Shakespeare in Love." She has also headlined the films "Emma," "Possession," "Sliding Doors" and "Iron Man."

Key to the Cure is a women's cancer initiative founded in partnership with EIF's Women's Cancer Research Fund.

Designer Karl Lagerfeld created a limited edition T-shirt that will retail for $40, with more than $35 going to charity, exclusively to benefit Key to the Cure. It is to debut at Saks Fifth Avenue Oct. 1. Paltrow will appear in a national public service announcement wearing the T-shirt.

Saks Fifth Avenue's charity shopping weekend will also take place Oct.16-19 at all of its stores nationwide and through saks.com, during which 2 percent of sales will benefit local organizations through EIF's Women's Cancer Research Fund.

"Key to the Cure is one of Saks Fifth Avenue's most important initiatives because of the numbers of people within our communities who are affected by cancer and depend on both the advancement of research and the efforts to ultimately find a cure," Steve Sadove, Chairman and CEO of Saks Fifth Avenue, said in a statement. "We are... truly privileged to have the support of Karl Lagerfeld and Gwyneth Paltrow in our momentous 10th anniversary year."