4/1 6:30 AM PT -- A memorial has been set up right next to the place Nipsey was murdered, with fans coming out in droves to mourn and pay their respects.

7:15 PM PT -- John Legend also just sent his condolences to Nipsey's family, but also revealed that he'd just finished filming a music video with the rapper a few short days ago -- Thursday to be exact. John says it's a song they collab'd with DJ Khaled for, and they filmed in Inglewood ... near Nipsey's stomping grounds.

The tributes have not slowed down at all either. Folks like J. Cole, Meek Mill, Pusha T, Issa Rae, Vince Staples, Jalen Ramsey, Marcus Stroman, Michael B. Jordan and more have commented on his death with remorse and shock.

Nipsey Hussle's murder has Hollywood in utter shock ... and tributes are pouring in from all over the hip-hop world and beyond.

TMZ broke the story ... Nipsey was gunned down Sunday outside of his Marathon clothing store near the Crenshaw area of LA. We're told a lone gunman walked up on Nipsey and his crew and fired multiple rounds before fleeing in what appeared to be a waiting vehicle.

Nipsey was pronounced dead at a hospital shortly after.

Drake was one of the first major artists to respond to the news that Nipsey was shot and killed Sunday outside of his clothing store in L.A. The Toronto rapper posted a photo of Nipsey on Instagram and added the caption, "F*ck. My whole energy is just at a low right now hearing this. We just linked for the first time in years and said we were gonna do a new song this summer cause it had been too long."

Drizzy added, "You were having the best run and I was so happy watching from distance fam nobody ever talks down on your name you were a real one to your people and to the rest of us. I’m only doing this here cause I want the world to know I saw you as a man of respect and a don. Rest easy my g."

Offset also posted his own IG tribute, saying ... "BLACK MAN ON A JOURNEY OF POSITIVITY KILLED THIS A SHAME TO OUR CULTURE REST UP HOMIE."

Chance the Rapper tweeted his condolences as well, saying, "RIP Nipsey man. This is tragic."

The tributes are still rolling in, but among the most notable so far is LeBron James, who was apparently a big Nipsey Hussle fan.

Bron wrote on Twitter, "So so SAD man!! DAMN man this hurt."

Snoop Dogg also paid tribute to Nipsey, posting a video an old video of the two of them rapping together. Snoop added a caption, saying ... "Gone 2 soon @nipseyhussle I’m so sad right now I’ll just reflect on the good times we had."

Rihanna responded as well, writing ... "This doesn’t make any sense! My spirit is shaken by this! Dear God may His spirit Rest In Peace and May You grant divine comfort to all his loved ones! I’m so sorry this happened to you @nipseyhussle."

Nipsey was 33. RIP