The rather coy looking One Direction singer was pulled from his seat next to BFF Ed Sheeran at the LA ceremony by hosts Darren Criss and Lucy Hale to get his Twerk on, much to the delight of the screaming crowd.
And it wasn't long before Harry (and his bum) were trending all over Twitter with the hashtag #HarryDroppedThatThunThunThun.
But as the video circulated around the internet, it seems Harry became a little embarrassed, later tweeting: "Note to self. Don't 'twerk'."
It seems he impressed Twerking pro Miley though, as the pair were later pictured cuddling up together backstage.
What a lovely couple they'd make, eh?
It was a big night for Harry who picked up the award for Choice Hottie and Choice Smile (yes, that's a real award), while One Direction scooped four of those famous surfboards for Choice Summer Tour, Choice Group, Choice Single ('Live While We're Young') and Choice Love Song ('Little Things').
They also opened the show with a performance of new single 'Best Song Ever', which you can watch below...