Venus and Serena Williams skip premiere of their documentary (TIFF 2012)

Attendees at one of Tuesday's movie premieres at the 2012 Toronto International Film Festival were confronted with an interesting question: if the two subjects of a documentary don't show up for the screening, does it really happen?

See also: More coverage of the 2012 Toronto International Film Festival

Obviously, yes, the film by journalists Maiken Baird and Michelle Major titled "Venus and Serena" did have its world debut at TIFF on Tuesday, and both women were all smiles as they greeted the media and fans on the red carpet. But it was impossible to ignore two glaring absences from the premiere: the Williams sisters themselves.

According to the L.A. Times, it took four years for the tennis champ siblings to sign off on the documentary about their lives. And once they did, Baird and Major recorded over 450 hours of material over the span of 20 months following the duo around the world, interviewing them and their family members. But after all that, the Williams sisters suddenly pulled their support from the filmmakers when they saw the finished version of the film and felt "unhappy."

See also: Michael Sheen tries to avoid Rachel McAdams' spotlight at TIFF

Though neither sister made any preconditions before shooting began, they were reportedly upset with the way their father Richard was portrayed. After the initial screening in August, Venus and Serena requested that changes be made to the film, which is mostly complimentary to the sisters but includes information about Richard Williams' 78-page manifesto for their success and other children he had outside of marriage.

The changes that Baird and Major made were not sufficient enough for the Williams sisters to continue to support the film or attend its premiere in Toronto, which was specifically arranged so that it would fall after the U.S. Open, which Serena won.

"It's disappointing to us… We have a lot of respect for them and think their story is very inspiring," Major told the L.A. Times.

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"We think this is an important story, and we can only hope Venus and Serena come to see it that way too," Baird added.

Representatives from the Williams sisters have not commented on the current relationship between them, the documentary, and the filmmakers.

Fans at the TIFF screening, though, were more vocal about the rift.

"I'm on their side. I don't blame them. I find the media always talks about them in a negative light," one fan said.

Added another, "If it was just going to be a marketing piece for the Williams family, what's the point?"

While Baird and Major look for wide distribution at the festival, hopefully many more tennis fans will see for themselves the reason for the lost love between the star athletes and the dogged journalists.