The former Fifth Harmony singer earned the first perfect score, a 30/30, of the season on Monday night's episode, wowing the judges with a stunning Paso Doble to her own song, "Higher."
Brooke, who performed with partner Sasha Farber, broke down in tears hearing the judges' praise of her performance. "It was a mix of good technique and high performance," Len Goodman exclaimed, while Carrie Ann Inaba noted Brooke's transformation to a "superstar."
"You came in and you were one of these girls from a girl group, and right now, you just proved to me and to everyone that you are a frickin' superstar! Something has shifted in you. You've commanded all of our attention," Inaba raved. "Ally, it's just amazing. My mind is blown and you better work, honey!"
After receiving her score, Brooke was overcome with emotion. "Oh my god. Thank you so much, just thank you! Tonight was so special. I'm just -- I literally cannot say how happy I am, and it's so special to be able to sing and dance to my own song," she said through tears.
"I love this show and what it's done for me and my confidence," Brooke added. Thank you so much. I'm just so thankful."
Despite her high scores, Brooke found herself in the bottom two later on Monday night's episode. The judges saved her from elimination over Kate Flannery -- but expressed their disappointment that both women were put in that position, with Sean Spicer saved, regardless of his consistently low scores.
"Maybe people think, 'Oh, she's got three 10s, she's good, we don't need to vote.' But vote!" Brooke told ET's Keltie Knight of the controversy after the show. "I'm just focused on my dance and the score -- because honestly that was a feat for me. That was a milestone."
Dancing With the Stars airs Mondays at 8 p.m. ET/PT on ABC. See more in the video below.