Today, Dolly Parton is a legend who has everything she could ever ask for, but she told ET her toughest days were the ones that prepared her the most for success.

"I think my childhood made me everything I am today," said Dolly, who grew up in extreme poverty. "I would trade nothing for being brought up in the Great Smoky Mountains. I've never been ashamed of my people no matter how poor or dirty we might have been. I've always loved being from where I am, and having the folks that I've had."

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Parton's inspiring story is being told in the upcoming TV movie, Dolly Parton's Coat of Many Colors, named after Parton's favorite song, which details her toughest childhood years.

"It's made me what I am," Parton added. "It's that spiritual base; it's that family; love of family; it's just that simple life, feeling like part of nature."

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Eight-year-old Alyvia Alyn Lind was handpicked by Parton to play her in the movie, set in 1955 Tennessee.

"The big Dolly Parton and the little Dolly Parton are very alike because they're both sassy, but they're both very sweet," Lind told ET.

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The movie, according to the official synopsis, is "neither a biopic nor a musical about Dolly's whole life and performing career, but rather a family-oriented faith-based story about the incidents in her and her family's life around the time she was 9 years old."

Coat of Many Colors airs Dec. 10 at 9 p.m. ET/PT on NBC.