Rap superstar Usher has become a shadow of his former self, and his one-time protégé Justin Bieber is worried sick, Breaking Celebrity News can exclusively reveal.

“Usher has become a total recluse and friends are worried about his increasingly dark state of mind,” said an insider.

As Breaking Celebrity News reported, two women and one man recently hit Usher with a $20 million lawsuit, accusing the bed-hopper of giving them herpes.

Compounding the 39-year-old “Burn” singer’s problems, he’s also now going through an ugly split from his wife Grace Miguel.

“He’s been through some turbulent times with the herpes lawsuit, and now he’s dealing with a divorce,” which exploded after his STD scandal came to light, said the insider.

“It’s turned Usher into a shut-in and he’s on the edge right now — he doesn’t want to work and he’s benched his touring plans for this year because of all these personal problems,” said the source.

Bieber, 24, hopes his old friend somehow finds a way to bounce back, especially since he hopes to involve him in one of the most important events of his life — Hailey Baldwin and his upcoming wedding.

“Justin would love to have Usher as a best man when he marries Hailey, but Usher’s too down right now,” said the source, adding the “Sorry” crooner is nonetheless “desperate to help him get back on track.”