Whoa -- talk about bad blood!

Justin Bieber has NO love for fellow chart-topper The Weeknd, and we're pretty sure it has something to do with the fact that the hitmaker is dating BIebs' ex Selena Gomez.

Cameras caught Bieber out on the town Friday night at Delilah and a paparazzo asked him if listens to the fellow Canadian's music. Bieber responded, curtly, with: "Hell no, I can't listen to a Weeknd song!" Bieber replied. "That s--t's wack." DAYUM!

After Selena was photographed with The Weeknd and Santa Monica hotspot Giorgio Baldi just over a week ago, fans have been wild with speculation that Bieber's jealous and upset. Well, it seems they're right!

Gomez and The Weeknd were spotted out again, recently, at Silver Lake nightclub Tenant of the Trees where John Meyer and Dave Chappelle did and impromptu performance.

Meanwhile, it's not just Justin who's upset, The Weeknd's ex Bella Hadid unfollowed Selena on Instagram after Gomez and her ex were spotted on the dinner date January 15th. When sexual partners rotate in Hollywood, there IS fallout!