Oops, they did it too...
Brit performed the video stunt, which sees people being filmed frozen in place mid-action, with her backup dancers onstage at the AXIS auditorium at the Planet Hollywood Hotel & Casino in Las Vegas at their Britney: Piece of Me residency show. Britney, who posted the clip on Instagram, has been performing at the venue since late 2013.
The video also touted Spears' latest accomplishment; She was named the best resident performer in the Las Vegas Review-Journal's 2016 Best of Las Vegas Awards, which are chosen by readers, for the second year in a row.
"We use our bodies to make our own #MannequinChallenge," Britney wrote. "THANK YOU for voting #PieceOfMe for @TheBestOfLV!!!"
Kate did the Mannequin Challenge at a garden party in Malibu with son Ryder Robinson, 12, and friends such as stylist Jamie Schneider Mizrahi, Sara Foster, Erin Foster and Rachel Zoe, who brought her son Skyler Morrison, 5.
"How'd we do?" Mizrahi asked.
Blac Chyna, fiancé Rob Kardashian and other loved ones also performed the Mannequin Challenge together recently inside her hospital delivery room. The two welcomed their first child together, daughter Dream Kardashian, Thursday.