The Hitch star agreed to be blasted with glitter in the promo after falling for her quirky pal's new single.
She tells EW.com, "He called me to be in the video, and I said, 'Yes'. I love the single. It sounds like old Prince. It just makes me want to dance."
And Mendes admits there's something she finds attractive about Har Mar Superstar: "To be an artist, it’s important to be utterly fearless. He’s not someone who’s conventionally attractive by society’s standards. But he is utterly fearless, and I‘m so attracted to that."