Janet Jackson became one of the greatest pop stars in history, thanks in no small part to the legendary albums she recorded in Minneapolis. She's also mastered the art of shutting out the world.

Trailers for "Janet Jackson," a four-hour documentary airing Friday and Saturday on A&E and Lifetime, promise that viewers will finally get the whole story. But it's a promise the film can't keep.

Part 1 gets off to a promising start. We learn upfront that a film crew has been embedded with Jackson for the past five years. Cameras follow her back to Gary, Ind., where she visits her childhood home for the first time since she's become famous. There's an especially touching moment when she coos over a mural of the Jackson 5.

We also find out in the first 10 minutes that Jackson and her brother Randy are executive producers. That's a red flag. Biographies controlled by their subject matters often come across as propaganda, even if that's not their intention. That's certainly the case here.

In the first two hours, the only part of the documentary available for review, Jackson finally denies that she had a child with her first husband, James DeBarge, saying that the rumors may have been fueled by the fact that she gained some weight while starring in the TV version of "Fame." But even though DeBarge is interviewed, he's not seen sharing his previously publicized belief that she did indeed have their baby.

Jackson also defends her father, Joe Jackson, who has been accused in the past of physical and mental abuse toward his children. She insists his toughness came from a place of love. Harsh criticism from other siblings, most notably La Toya, are not included.

While the long-anticipated project may lack balance, it does feature some tantalizing never-before-seen footage shot by Jackson's second husband, Rene Elizondo Jr., who was with her when she recorded "Rhythm Nation 1814" in Minneapolis.

In one scene at Flyte Tyme studios, producer Jimmy Jam is urging Jackson to sing with more emotion. When she gives it another shot, Jam and his partner, Terry Lewis, start giggling. Jackson erupts.

"I don't need this," she says as she walks out. "This has gone too far."

At one point, Jam tells Elizondo to turn off the camera. But he doesn't comply.

In new interviews, Jam and Lewis have plenty of great things to say about their relationship with Jackson. They're just some of the big names weighing in on Jackson's legacy. Others include Missy Elliott, Samuel L. Jackson, Mariah Carey, Lee Daniels and Paula Abdul.

The final two hours, premiering Saturday, are expected to cover Michael Jackson's legal troubles and the Super Bowl debacle with Justin Timberlake. If the first half of "Janet Jackson" is any indication, don't expect her to go deep.

'Janet Jackson'

When: 7 p.m. Friday and Saturday.

Where: A&E and Lifetime.