This relationship is heating up! Justin Bieber and Hailey Baldwin were on the set of an upcoming secret project by DJ Khaled in LA on Tuesday and we spotted the couple hugging and JB carrying his g-friend across the set. Our photographer on the scene tells us: "Justin and Hailey were giggly and cuddly. She jumped into his arms and he was joking and laughing, giving her a ride to the set." Cute!

The couple recently reunited in Miami at the VOUS church conference with their Hillsong family -- it's their faith that brings them together every time! After that, the couple jetted to NY where they spent a romantic few days bumming around the city, holding hands, making out on sidewalks and in parks ... and now they flew back to LA together and they're inseparable!

Justin's collabing with DJ Khaled again after the duos first project together, "I'm The One," went platinum like a bazillion times. This new project is "top secret," according to Khaled and the uber-producer's doing what he does best and teasing it on social media. Check out the pic AND the video Khaled Snapped -- in which he gifts Justin with a ROLEX! Yes, a Rolex, y'all ...