"Happy birthday to this magic human," wrote Cabello. "I love you!!!!"
Cabello and Mendes have been friends for a while now, having collaborated on the 2015 track "I Know What You Did Last Summer" before their steamy 2019 duet "Senorita." They previously denied rumors that they were an item, claiming that they were just friends. But, to quote the couple's new song, "friends don't know the way you taste." This summer, Mendes and Cabello were spotted making out in Miami. Is Shamila...on?
It's possible. Cabello recently ended things with boyfriend Matthew Hussey, while Mendes' last high-profile alleged relationship with Hailey Baldwin seemingly ended before Baldwin's relationship-turned-marriage to Justin Bieber heated up.
If these two are working on a relationship and not just music, Mendes and Cabello have kept things pretty private on social media. They've shared behind-the-scenes footage from their new music video, but nothing too personal — and definitely nothing that would imply they were a real-life couple. Even this birthday message (which features a pic that's pretty platonic looking in nature, if we're being honest) could technically be interpreted as nothing more than one friend shouting out another on their b-day.
The lack of comment from the maybe-couple hasn't stopped fans from speculating that a Twitter message from Cabello — "I think you’re gonna change my plans" — could be about a budding romance with Mendes.
Boyfriend and girlfriend, or just occasional kissing buddies who have recently discovered the way the other tastes, we don't know. One thing we do know is that whenever these two get together, sweet music is made. That's the real thing to celebrate here — in addition to Mendes' 21st birthday, of course.
Refinery29 has reached out to Mendes and Cabello for comment.