The One Direction heart-throb popped the question to a fan who'd dressed as a bride at the band's gig in Philadelphia after he picked her out of the sell-out crowd and joked he didn't want her efforts to go to waste.
While the boy-band were thanking the audience at the end of their gig, Harry said: 'I heard there was a girl here in a wedding dress ... is there a girl here in a wedding dress?
'Now I feel bad letting this go to waste so what's your name? Preeya? Preeya ... will you marry me? There's been a plot twist! OK .. awesome'
The 20-year-old singer then joked that he and his new love were going to wait until everyone had sent them presents to celebrate their engagement before calling it off.
He added: 'We'll take the engagement gifts and then we'll ... OK, awesome. I almost wore my wedding dress. It could've been awkward. But that's a different story.'
One Direction will be in concert throughout the United States until the final performance of their tour in Miami on October 5.
Claudio Encarnacion Montero, Harry Styles and Justin Bieber (Getty)
