The evolution of the Carl's Jr. girl, from Paris Hilton to Hayden Panettiere

In 2016, Carl's Jr. and Hardee's want spokeswomen with both cleavage and complexity. 

"At one point in time, we were using 'Sports Illustrated' swimsuit models," Andy Pudzer, CEO of Carl's Jr. and Hardee's parent company CKE Restaurants, told Business Insider. "Now, because of the impact of the millennial generation, we're probably using people who not only have been gifted genetically, but who also... work on a number of levels with our ads."  

The latest of these multi-talented women is singer and 'Nashville' star Hayden Panettiere, who appears in the company's latest commercial, sensually chomping down on the new Midnight Moonshine Burger.

The burger chain's ads have gotten plenty of press for starring scantily clad women. Here's how the company's racy marketing strategy has evolved over the years.