Prince*According to Prince’s ex, Charlene Friend, the late singer’s half-brother, Duane Nelson, once told her that the music icon lived on a “cocaine diet.”

Friend insists she never witnessed him take drugs, but she claims his half-brother did. Prince died in April at 57 from an alleged overdose of Narcotic Fentanyl.

Friend said Duane — who died in 2013 — once told her, “We call it the cocaine diet.”

“It was shocking to me to hear that. He hid it so carefully. I never saw him take even an aspirin. He seemed so health-conscious, always taking vitamins like Echinacea and Goldenseal.”

RollingOut.com notes that the “44-year-old interior designer — who dated Prince for two years after meeting him in 1989 — also claimed the star went up to five days without sleep but when he did get some shut-eye, he covered the windows in aluminium foil to make sure the room was pitch black and turned the heat up to 80 degrees.”

READ RELATED STORY: Apollonia Posts Lengthy, Emotional Letter to Prince: ‘I Feel Like Your Widow’

She added to PEOPLE: “He would sometimes stay up for five days at a time without sleep, food or even water, going nonstop back and forth to the studio. I had to sneak in catnaps to keep from passing out from exhaustion. The first time that happened, I asked him, ‘How do you do this?’

“He would be shaking all through the night. The first time that happened, I asked him if he was having a nightmare and he said, ‘No. I was dreaming music.’ Even in his sleep, the music just poured out of him.”

Friend also reveals how mutual pals said Prince was “taking pills to come down” from the high he got from performing.

In 2003, Friend sued Prince for emotional distress and defamation, claiming she was psychologically abused during their relationship.

She claimed in court documents: “Prince informed me he took sexual relations very seriously. He believed he was the Messiah and if you engaged in sex with him, you became one with him.

“He would have me dress in his clothing at his whim. His staff [was] not allowed to look at me and I was not allowed to look at them.”

Prince won the case after his legal term proved he was the victim of a “spiteful lawsuit.”

In related news, Prince’s Revolution reunited for the first time in five years Thursday night at First Avenue, the Minneapolis club their late bandleader made famous in Purple Rain.

“I encourage every one of you to take every one of these songs and make them your own,” urged guitarist Wendy Melvoin.

RollingStone.com reports that the band’s set list included the following songs:

“Let’s Go Crazy”
“Computer Blue”
“America”
“Mountains”
“Do It All Night”
“Let’s Work”
“Uptown”
“Party Up”
“Little Red Corvette”
“1999”
“Sometimes It Snows in April”
“Raspberry Beret”
“The Beautiful Ones”
“Private Joy”
“When Doves Cry”
“Controversy”

Encore:
“Kiss”
“Baby I’m a Star”
“Purple Rain”