Gisele Bündchen is the brand's first spokesperson who isn't a professional athlete.

A fashion model probably doesn't fit your definition of an athlete. But Under Armour's latest “I Will What I Want” campaign (remember that crazy motivational video of Misty Copeland?) is challenging you to rethink the notion that people fit into neat little boxes.

On Tuesday, the brand announced that they'd signed supermodel Gisele Bündchen by posting a teaser video of the lithe 34-year-old preparing for a kickboxing workout. She is their first spokesperson who isn't a professional athlete. (ESPN reports that Gisele signed a multi-year deal, joining her husband, New England Patriots quarterback Tom Brady, who linked up with Under Armour in 2010.)

Today, the company unveiled the full 1-minute spot where Gisele kicks and pummels a punching bag as mostly negative tweets about her latest gig are projected on the walls behind her. "Stick to modeling sweetie." "Under Armour WTF?" "Is modeling now a sport?" "Gisele is not an athlete."

Under Armour knew that people might be skeptical of their latest spokesperson—and that was part of the point.

"Most women at a certain point in their life encounter contradicting opinions, expectations, praise and criticism. Having lived her life in the public eye since she began modeling at 16, Gisele knows what it means to focus inward in order to beat the noise and achieve her own goals," Leanne Fremar, Senior Vice President and Executive Creative Director, Under Armour Women's said in a release. "Along with scaling to the heights of her profession as a model and a global fashion icon, she's an incredibly athletic woman, dedicated to her practice of martial arts and yoga."

As the social media chatter about Gisele continues, people can see comments updated in real time (with some moderation) in three more of her workout videos on the Under Armour site.

In addition to Copeland and Bündchen, Olympic skier Lindsay Vonn, tennis player Sloane Stephens, and soccer star Kelley O’Hara are also involved with the “I Will What I Want” campaign.