There is a scene in "The Clark Sisters: First Ladies of Gospel" in which choir director Mattie Moss Clark scares the bejesus out of the audience. Someone in the chorus is off - way off - and Clark is not having it. She throws one of her sensible shoes, snatches up a tissue and snatches off a few wigs.

"Spit the gum out!" Clark demands of the offending soprano. "Now if y'all weren't coming up in here chewing gum you might be able to sing," she barks before turning the screw even more. "Might! Ya might!" The character teeters between terrifying and awe-inspiring, and the actress so precisely walking the edge smacks you back to every embarrassing rehearsal there ever was. You recognize her but perhaps can't quite put a finger on how.

Because you know who Aunjanue Ellis is even if you don't know who Aunjanue Ellis is.

She is the woman scorned, chucking a brick at a car window in "Ray," the holier-than-thou monster-in-law of "If Beale Street Could Talk," the mother on a mission in "When They See Us" and so many scene-stealing characters in between. But her biggest role yet? The career-definer? A Lifetime biopic that premiered in the midst of a pandemic.

In "The Clark Sisters," Ellis plays Dr. Clark, a world-renowned music director whose five daughters formed the best-selling gospel girl group of all time. An exacting matriarch and musical genius, Clark was Joe Jackson and Berry Gordy rolled into one. And yet - much like the actress who embodied the role - she isn't a household name. But that was then.

"Aunjanue Ellis shows up as Mattie Moss Clark in each and every scene, and my job at that point is to get out of her way. I'm not even joking," said Christine Swanson, the film's director. "It was like she was possessed."

With 2.7 million people tuning in to the April premiere, "The Clark Sisters" had Lifetime's biggest movie debut in four years. Ellis as Mattie takes up most of the screen, and fans noticed. "All week I've been in awe of how Aunjanue Ellis BODIED her role in The Clark Sisters movie," wrote one Twitter user.

"Aunjanue Ellis is acting for the gawds!" raved another.

Perhaps the highest praise came from Kierra Sheard, who played her own mother, Karen Clark Sheard, in the film. "Aunjanue Ellis, she merked my grandmother's role and she did it so well to where there were moments where I was just kind of crying to myself in my dressing room," Sheard told Essence magazine.

Swanson said the women who played Clark's daughters, all incredible singers but relatively unknown actresses, were responding to something real in their scenes with Ellis. The veteran actress' energy as Mattie Moss Clark was that palpable. "She had such a dominant presence," she said. "To be able to hold that space with that level of precision? She just made everybody else stand up straighter."

"Her gift is so explosive that I keep scratching my head like, why isn't she a household name?" added Swanson. "It took this role to allow people to see how bada-- she really is."

For her part, Ellis said difficult women are her favorite to play; cute and cuddly isn't her speed.

"I love folks who make you uncomfortable. That's who Dr. Mattie was. She made people uncomfortable because she was pushing people to be better than they were," she told The Washington Post.

Ellis' ultimate goal was to make the Clark Sisters, whose music she described as her "lifeblood," proud of the project. "We didn't want to embarrass ourselves and didn't want to embarrass the Clark Sisters," she said. "All of this is just that extra thing," she said, referring to the praise being heaped on her performance.

Digging into exactly how she was able to melt into Clark's character, Ellis explained that she approached the role as a student first.

"You have to look at that as another culture that you have to know and study and respect. I see representations of church life all the time, and I can tell them folks ain't never been to church," said Ellis, who pulled from her childhood growing up as a Baptist and going to church two to three times a week.

She found every video she could featuring the gospel director. She even found audio of Clark conducting one of her famously big choir rehearsals and pulled lines directly from those workshops to use in the film.

"I would wake up in the morning listening to her. I'd go to bed at night listening to her," said Ellis, who found common ground with Clark in her Southern upbringing. She is from Mississippi, and Clark was originally from Alabama. "I could just speak in my Southern self and pull from all of that."

"There was no part of myself I had to keep at bay to play her," said Ellis.

Ellis said she sees the biopic as, first and foremost, "a celebration of black women genius." She wants viewers to come away from the film with an understanding of how influential the Clark Sisters were to American culture and music.

African American female entertainers, she said, are often praised only as performers but never as musical geniuses heralded for their compositions, musicianship and arrangements. "We do that work, too," said Ellis.

"If I have a purpose in life, I want to correct how black women have been maligned. I feel that what I do is nothing less than a mission to correct that."