In the clip, Brook showed her viewers she had a new FaceBook friend suggestion which happened to be for one Abby Lee, who was known to be quite tough on the girls during practices, often reducing them, and their mothers, to tears.
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After she displayed the notification on her laptop, Brook turned the camera to herself and shook her head as if to say "no way" while adding a grimace.
Well, that didn't sit well with JoJo who got to defending her mentor with a few clacks of the keys.
"It's one thing to just not add her back, it's another to post..." JoJo wrote in the comments section of the TikTok.
While Brooke and her sister Paige severed ties with Abby Lee after their mom, Kelly, was charged with assault for an altercation with the dance teacher (the charges were later dismissed), JoJo has maintained a relationship with Abby Lee.
In an interview with US Weekly, the viral sensation said she was sad about the state of affairs between Abby Lee and other "Dance Moms" participants.
"I actually talk to Abby the most out of anybody from the show," she explained. "I think Abby got hurt by a lot of people and it's really, really, really sad that a lot of the people don't talk to her anymore."
Meanwhile, JoJo recently shared a TikTok "wipe" where she traded in her flamboyantly accessorized hair for a more "mature" look.
All on the eve of her 17th birthday.
As for Brook, she has yet to respond to JoJo's comment.