In the opening scene of the first film biography of Pulitzer Prize-winning author Alice Walker, she says people have always had a problem with her.

"They had a problem with my disinterest in submission. My intellect. My choice of lovers. My choice of everything. Choose one. Choose all. They just had a problem."

Emphasis on they. "Beauty in Truth," which airs on the PBS "American Masters" series, offers an unprecedented look at a the private life of a fearless writer whose every move has been second-guessed by polite society, whether she was defying the plantation landlord who wanted her to pick cotton and instead going to elementary school; marrying a white man in the middle of Klu Klux Klan territory; or capturing the 1983 Pulitzer for "The Color Purple," a novel about black women in rural Georgia in the 1930s that drew venom from African-Americans for portraying rape, incest and a love affair between two women within the black community.

Alice Walker as a child in a personal scrapbook. (PBS)

"I don't know if I've ever cared much what others think," Walker said in a phone interview from her winter home in Jalisco, Mexico. "I've always felt quite singular, even as a child. That I must stay on track to keep my purpose."

The PBS film tracks Walker's route from the daughter of sharecroppers in the Jim Crow South; to Spelman College in Atlanta, where she found a mentor in historian-activist Howard Zinn and marched with Martin Luther King Jr.; to Mississippi, where she and her husband got married before interracial marriage was legalized; and to New York, where she was heavily involved in the formation of Ms. Magazine. Her literary rise, global activism and Buddhist spirituality are highlighted.

The author granted unprecedented access to filmmaker Pratibha Parmar, who befriended Walker in 1993 when the pair traveled to Africa to make a film version of Walker's book about female genital mutilation, "Possessing the Secret of Joy."

Parmar was given access to Walker's family photo albums, her private journals, and her homes in Mexico and Mendocino. Parmar, who teaches film at California College of the Arts in San Francisco, discovered startling things about her friend and colleague while making the documentary.

"I had read that Alice was born on a plantation and lived in a shack in Eatonton, Ga., but actually seeing the footage and listening to Alice's stories about how her mother saved up money to buy wallpaper for Alice and her sisters yet ironed brown paper bags for her own room, it was a startling illustration of the level of poverty that Alice grew up in that I really didn't know."

The documentary includes interviews with her siblings; her contemporaries, including feminist author Gloria Steinem and actor Danny Glover; as well as Steven Spielberg and Quincy Jones, who produced and directed the film version of "The Color Purple."

Her former husband, attorney Mel Leventhal, talks about their passion for civil rights and art, plus the racial tension from both bigots and activists alike that strained their marriage and eventually pulled them apart.

But noticeably absent from the film is their daughter, Rebecca, 44, an author who has written about the abandonment she felt by her famous feminist mother.

In the film, Alice Walker talks about leaving a young Rebecca with the family downstairs when she had to travel for work. Today mother and daughter are estranged.

Parmar said this was the most difficult subject to tackle in the film, which she did by having Walker read a poem about imagining meeting her grandson, over images of Walker's laundry billowing in the breeze.

"It's part of my story, and Pratibha handled it with great tenderness so no one was bruised," Walker said. "I will always love Rebecca. It's not possible to stop love."

Currently Walker is assembling her lifetime of journals for publication. The national premiere of "Beauty in Truth" coincides with her 70th birthday Sunday, which she plans to spend quietly at home with "my sweetie and my dogs."

She hopes audiences enjoy the film.

"I hope they see it and feel happier and more adventuresome," Walker said. "That's the thing about life. It has so many incredible twists and turns."

What: "Alice Walker: Beauty in Truth" -- Documentary in "American Masters" series

When: 3:30 p.m. Sunday

Where: TPT