Prince's "Purple Rain" co-star Apollonia Kotero has opened up about the pop legend's death four months later, professing a love that endured for decades.

The model and actress starred in the iconic 1984 film as a character by her own name, the competing love interest between fledgling musician Prince -- "The Kid" -- and headliner Morris Day.

Unlike many Prince contemporaries, Kotero stayed silent after the pop legend's sudden April 21 death as she asked for privacy.

But she recently made a surprise appearance at a Los Angeles screening of "Purple Rain" and followed up this week with a lengthy letter on Facebook in which she said she felt "unbearable" pain since Prince's death.

"My life has been a vortex of rage and despair. Waves of sadness washing away the pieces of my broken heart. My own personal hell on Earth. I feel like your widow," she wrote.

She recalled visiting Prince at his Paisley Park estate outside Minneapolis in June 2014 and telling him that "when you love someone so much for so long, you become as one."

"I said to you the entire world calls you Prince, but to me you are a King. We kissed. We both had tears. I leaned my head on your shoulder. You celebrated us that night. Our 30th anniversary," she wrote, referring to the three decades since "Purple Rain."

She said that Prince sat her on a stage at Paisley Park and serenaded her with a private concert backed by 3rdeyegirl, the all-female trio that played with Prince late in his life.

She said that Prince told her that "This Could Be Us," his 2014 song with echoes of his powerful early ballads, was written about them.

Prince, who was 57, died from an accidental overdose of powerful painkillers.

Prince left no will and had no recognized children, leading to disputes over who will inherit an estate valued at hundreds of millions of dollars along with a vast vault of unreleased material.

A Minnesota judge on Thursday assigned a laboratory to administer a DNA test on Carlin Williams, an imprisoned little-known rapper who says he is Prince's son, by September 21.

Williams and his mother said that she had sex with Prince in a Kansas City hotel in 1976. He requested a new genetic test amid reports that a first examination did not ascertain that Prince was his father.

Prince had a sister, Tyka Nelson, and five half-siblings who under Minnesota law would have rights to the estate.

The family has assigned day-to-day affairs to a private administrator, which plans to open up Paisley Park -- a sprawling studio complex that held mythic status for fans who entered it -- to paid tours starting in October.