The black and white clip features the pop star singing inside a mostly empty building as he plays a piano and works out on a treadmill.
"I can't write one song that's not about you/ Can't drink without thinking about you/ Is it too late to tell you that/ Everything means nothing if I can't have you?" Mendes sings on the track.
"I Can't Have You" is available on music streaming platforms.
Mendes last released a self-titled album in May 2018. The release featured the singles "In My Blood" and "Lost in Japan."
Mendes will be the musical guest on Saturday Night Live on Saturday, which will be hosted by Adam Sandler for the first time.