Continuing in a long line of celebrity faces, Shawn Mendes is the latest talent to front a Calvin Klein Underwear campaign. The 20-year-old singer follows in the footsteps of the Moonlight cast and Justin Bieber. The Lost in Japan singer took to his Instagram to unveil the news with a look at the upcoming campaign. Mendes poses in a kitchen as he shows off his six-pack and Calvin Klein's latest underwear styles. Not his first campaign outing, Mendes also worked with Emporio Armani.