Taraborrelli wrote about one instance in 1986, when Jackson visited Ross backstage at Caesar's Palace in Las Vegas. When she returned to her dressing room, Jackson was putting on her makeup, transforming himself into Ross.
The writer also said Jackson once demanded that a chauffeur driving him around Beverly Hills that he address him as "Miss Ross."
In his autobiography "Moonwalk," Jackson called Ross "my mother, my lover and my sister all rolled into one."
Taraborrelli has said there was no sexual relationship between the two.
Nonetheless, in "Call Me Miss Ross," Taraborrelli wrote that Jackson was heartbroken when Ross got married for the second time to Naess. Jackson did not attend the wedding, telling Taraborrelli, "I was jealous, because I've always loved Diana Ross and always will."
Ross may have felt more motherly toward him. When Jackson moved to Los Angeles at the age of 9 to continue his recording career with Motown, he lived with Ross for a time.
The two stars shared a lot in common. Both started at Motown and became worldwide pop stars. Both earned diva reputations for their outsized lifestyles. And both were accused of selling out and turning their backs on their black heritage.
When Jackson collapsed during a rehearsal for a cable TV concert in 1995, Ross rushed to his bedside at a hospital in New York.
Biographer Brown said he wasn't aware that Ross and Jackson were close in recent years, but the fact that he included her in the will, he said, "just reiterates that she was his idol."