The actress has made her debut as the face of the brand, headlining a new ad campaign for its skincare line, the iD Collection, a custom blend hydration system available in 20 different combinations.
"It's wonderful, and humbling to be the first ambassador," Clarke tells People. "I love Clinique as a brand because it's universal and relatable."
The 33-year-old also insisted she is a longtime fan of the company's products.
"I'm not about to sell something that I've never tried," she adds. "I'm authentic."