Jesy Nelson grabbed her crotch and flashed her bum in a raunchy routine alongside her Little Mix bandmates.
On Sunday, the band performed live at the BBC Radio One Big weekend in Middlesbrough.
Sporting a black and green leotard, which was unzipped to show a PVC bra, Jesy didn't hold back as she let loose while the band sang their hit track, Touch.
The singer also sported thigh-high leather boots during the gig with bandmates Leigh-Anne Pinnock, Perrie Edwards and Jade Thirlwall.
Jesy took to Instagram on Sunday to share a string of photos from the gig, including one with her bandmates and another with her boyfriend Love Island star Chris Hughes.
In one photo, Jesy showed off her racy outfit and her followers couldn't get over it.
Britain's Got Talent judge David Walliams joked: "That is my exact outfit for BGT tomorrow."
A fan commented: "You’re killing it woman," while another wrote: "You left us all shock today that’s all I can say."
Little Mix became the first girl band to win The X Factor in 2011.
You left us all shock today that’s all I can say.
Following their performance at BBC Radio 1's Big Weekend, Perrie and Jesy revealed they have had drunken kisses just weeks after Spice Girls singer Mel B claimed she and bandmate Geri Horner had a steamy one-night stand.
Chatting to The Sun, Perrie admitted: "Of course there has. Me and Jesy get together all the time, especially when we’re drunk."
However, Perrie insisted their kiss was nothing more than just a bit of fun.
She added: "It was funny, but we are like sisters."
Both of the stars have boyfriends, with Perrie dating Liverpool star Alex Oxlade-Chamberlain for nearly three years while Jesy has found love with Chris.
Jade told The Sun: "Maybe there could have been a bit more in place for mental health, we all have suffered in some way.
"As four young women getting thrust into the industry, having everyone talking about how you look, just the pressure suddenly being in this industry was a lot for all of us. We had to find our own way of dealing with that."
Speaking about how the band coped with the demands of fame, Jade said: "We’ve got each other. We've all gone through moments with our mental health, whether it's talking to someone, getting therapy."
Let us know what you think of this story by leaving a comment on our Facebook page @EntertainmentDailyFix!