Whether she ever attended a full performance of "Dreamgirls" on Broadway is a fascinating mystery. She maintains she did not, often telling the press, "I didn't want to validate it in that way."

But some sources say she snuck up to a side balcony of the Imperial Theatre one night where she watched the show, unseen by the masses below. Another oft-repeated account claims she attended just the first act, then, horrified, stormed out at intermission.

"I think it would be very hard for Diana to resist seeing it," says Taraborrelli. "It's likely that she did sneak in and take a look at it. It's also likely, if that did happen, she would not have made a spectacle rushing out during intermission. But, officially, she maintains that she did not see it."

For the most part she's remained mum about her displeasure over the stage show since she's had close personal ties with people associated with it -- most notably, one of its original producers, David Geffen, who is now chief producer of the film.

"In the 25 years since the show opened, Diana has remained good friends with Geffen and has never mentioned it to him," reports her longtime colleague and pal. "She didn't want them to have an argument, so she's avoided the topic completely."

Ross was also best friends with Suzanne de Passe, who managed Jennifer Holliday, who played the Florence Ballard/Effie role. De Passe was a Motown exec who managed many of Ross' concerts and TV shows, too -- she even cowrote "Lady Sings the Blues."

"Because of the relationships she had with Suzanne and David, Diana felt that something should have been worked out" about "Dreamgirls," Taraborrelli adds, "and I'm not saying in a financial realm. I'm just saying in terms of her participation or cooperation or at least running it by her. She really had no pre-warning that the show was going to be so close to her life story."

The key difference between the "Dreamgirls" story and the Supremes in real life is what happens to Effie/Florence Ballard, the girl group's chubby lead singer who was pushed aside in favor of the slender/sexy Deena Jones/Diana Ross.

In real life Ballard suffered from such chronic depression that she was eventually dropped from the group.

Afterward, she failed to launch a solo career and died in poverty at age 32 in 1976. In "Dreamgirls," Effie rebounds after the split, has a hit music record and reunites with her ole galpals for a final farewell concert.

Some observers believe that "Dreamgirls" wasn't created as a fictionalized account of the Supremes in order to stiff Diana Ross and Mary Wilson out of financial compensation and story control, but because such tinkering with history was necessary in order to create a story that would work better on stage and screen.

That's a compelling argument and one that's forced Ross to be cautious about how strongly she expresses her disapproval of "Dreamgirls."

"Diana's really got to walk a fine line as not coming off as being against the film or being unreasonably angry about it," says Taraborrelli. "By the same token making it clear that one day she should, and hopefully will, do her own life story on her own -- like what Tina Turner did with 'What's Love Got to Do with It.'"

Meantime, Ross must decide how she'll respond publicly to the "Dreamgirls" film since journalists are certain to hound her for comment.

"She'll never support it," insists her longtime colleague and pal, who claims Ross may even be tempted to blast it publicly. "I wouldn't be surprised if she just finally blurted out what she really thinks about 'Dreamgirls' and let everybody have it. Remember who we're dealing with here -- a great diva!"