Fans gathered at Paisley Park, Prince's home and studio, on Thursday night as part of Celebration 2017 -- 4 days of concerts honoring the legend who died a year ago today. Huge bouquets of purple balloons flew outside the event.

And there's this ... Morris Day -- lead singer of The Time and Prince's nemesis in "Purple Rain" -- released a new song in his honor ... "Over That Rainbow."

Morris told Rolling Stone the last time he saw Prince, "I thought maybe something wasn't right. I thought, he looked thin, even though he always looks fragile. After he passed away, I just wondered if he knew something that he wasn't telling me. I just felt like he knew. Like he knew that something wasn't right."

#RIPPrince