Ariana DeBose is in mourning after the loss of her mom and "best friend."

The Oscar-winning "West Side Story" star, 34, shared in a touching Instagram post on Aug. 19 that her mother, Gina Michelle DeBose, has died at age 57 after a three-year battle with ovarian cancer.

"She was my favorite person, my biggest fan and toughest critic," DeBose said. "My best friend. She was my date to every important moment in my professional and personal life — and I wouldn't have it any other way. It had always been the two of us for as long as I can remember. She fought like hell to give me a good life, a good education and every opportunity in the world. I wouldn't be where I am without her."

DeBose grew up in North Carolina, and her mother, a social studies teacher, raised her as a single parent.

"Because it was just the two of us, we kind of raised each other," the "Hamilton" alum told Tamron Hall in 2023.

In a 2016 interview with The Great Discontent, DeBose shared that she and her mom "lived with my grandmother for a portion of my youth," and her mother and grandmother helped her get into dance. "It was financially challenging because, at that point, it was just me and my mom," she said. "She was starting out in her professional career, so it was tough, but she took me to Dance Theater of New Bern."

In her Instagram tribute, DeBose noted her mother's "life's purpose, aside from being my mom, was educating young people," and she had almost 30 years of experience as a public school teacher.

"My greatest and most proud achievement will always be to have made her proud," she added. "I love you mommy. Now travel amongst the seas, the winds and the angels as I know you always loved to do."

DeBose also said that she "couldn't be more proud of her and how she fought this insidious disease" for three years. According to the American Cancer Society, more than 20,000 women will be diagnosed with ovarian cancer in the United States in 2025.

When DeBose won the Oscar for best supporting actress in 2022 for "West Side Story," she shared a hug with her mom, who joined her at the ceremony. DeBose also thanked her mom in her acceptance speech, saying, "I love you with my whole heart, and this is as much yours as it is mine."

DeBose's mother visited the set of "West Side Story" during filming and met director Steven Spielberg, the actress told People. "Watching Gina become speechless was amazing," she told the outlet.

Speaking with USA TODAY in 2020, DeBose also opened up about getting support from her mom after coming out as queer at age 11.

"I was like, 'Mom, I think I could like boys and girls,'" DeBose recalled. "'I just really like humans.' And she said, 'OK. Cool.' That was it. And I realized how lucky I am to have had that experience, because that is not the norm."

This article originally appeared on USA TODAY: Ariana DeBose mourns death of her mom at 57: 'My favorite person'

Reporting by Brendan Morrow, USA TODAY / USA TODAY

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