Justin Bieber, Ty Dolla Sign, MGK Mourn Slain Rapper Chris King

Justin Bieber , Machine Gun Kelly , Ty Dolla $ign and several other huge artists are taking the loss of rapper Chris King hard, after the Nashville native was gunned down on April 20.

According to the Metropolitan Nashville Police Department's report , Chris was standing in an alleyway with a group of friends around 2:30 AM Saturday when another group of people attempted to rob them.

Gunfire erupted, striking Chris and another man ... and both men fled the scene in separate directions.

The victims ended up at Vanderbilt University Medical Center for treatment, but Chris succumbed to his injuries ... leaving his famous friends stunned.

Bieber and Chris were once close enough to live under the same roof, and the pop star didn't hold back his emotion, writing in his tribute ... "Love you bro. This one hurts. Please keep his family in your prayers. See you in paradise brother.”

Trippie Redd credited Chris for introducing him to 10K Projects boss Elliot Grainge -- a meeting that would change his life -- and MGK, DJ Paul and several other artists also shared condolences in his comment section.

Chris' top song "Evil Kunevil" features Trippie, and he was the CEO of his own Snotty Nose Records.

He was only 32.

RIP