The stars, broadcasting from their separate homes, took turns to recreate popular routines from the app.
The dances started off slow and easy and, yes, they both nailed it.
The idea is that they both watch a TikTok Challenge that neither of them had seen before and then try to recreate it.
"I'm gonna go down in flames in front of my kids, it's fine", JLo laughed. "It was Tuesday or Wednesday and we were supposed to be finishing on Sunday, but they came to us and said, 'We have to finish by Friday".
Watch the stars of TikTok as Charli D'amelio and Addison Rae to stop a movement before having to re-create it by themselves proves to be hard, even for a pro as experienced as Jennifer!
Meanwhile Jimmy seemed to struggle with a number of the dances and often resorted to making up his own moves.
"That wasn't bad! It's hard to do these in one thing", Jennifer assures her dance off partner.
On her Instagram stories, she also shared a video of the dance and encouraged others to attempt it.