The Cougar Town actress will represent a new line called Pantene Expert Collection, which features anti-aging hair products, reports WWD.
Cox shared: "I've always been a fan of Pantene. I was not expecting how my hair was changing as I got older. [It] was starting to get dry, brittle and thinner."
The ad campaign will be unveiled in October, before the release of the Pantene Expert Collection in November.
Cox and her co-stars recently appeared in a new video announcing the season four premiere date of their show Cougar Town.
Cougar Town is set to air on January 8, 2013 on its new home TBS, which picked up the series after its original home ABC.
Watch Courteney Cox and her Cougar Town co-stars below: