Rob Gronkowski celebrated Avicii's life EXACTLY the way the DJ would've wanted ... so says another world-famous DJ, who tells TMZ Sports Gronk put a little happy into a terribly sad situation.
We got Gianluca Vacchi (yes, he's Italian) -- the dude GQ once called "The Coolest Man On Instagram" -- and asked him what he thought of Gronk turning up to Avicii's song in Austin this weekend.
You can tell Vacchi (who's remixed Avicii's music in the past) was moved by the tribute, telling our camera guy having fun is the whole point of EDM, and the perfect way to honor the late DJ.
Sad story, but you know what's not sad? Vacchi's Instagram. Dude has over 11 million followers and we gotta say his lifestyle makes Gronk look like Peyton Manning.
RIP Avicii.