Shawn Mendes and Camila Cabello Fully Back Together After Coachella Hookup

Shawn Mendes and Camila Cabello didn't just hook up for old time's sake at Coachella ... they seem fully back together, and we know that from a 3-second video shot Wednesday!

Shawn and Camila were hand-in-hand, strolling down a street in Santa Monica ... near a bank of restaurants.

As we reported, they met up at Coachella last weekend and were smooching, hugging and dancing ... but the prevailing view was it was a one-off after their breakup a year ago.

Not the case -- clearly. Here's the mystery ... did they just happen to see each other at Coachella, was there planning, and could they have gotten back together even before the music festival?

S&C first began dating in July 2019, and quarantined together during the pandemic.

There was lots of buzz he recently hooked up with his chiropractor, Dr. Jocelyne Miranda, but that doesn't appear to be the case ... Jocelyne was at Coachella with Shawn and saw it all -- highly unlikely they were anything more than friends.