Harry & Emily It's On!

SPARKS FLY Harry and Emily were "all over each other" on the streets of Tokyo, says an eyewitness.

Stabbed in the back? Olivia Wilde's ex Harry Styles moves on with her friend Emily Ratajkowski 

They were going at it and didn't care who saw them. Harry Styles and Emily Ratajkowski made out on a bustling street in Tokyo on March 25. Video of their randy encounter - which immediately went viral shows Emily holding Harry's hand and tenderly grabbing his face as she deepens their kiss, both of them completely disinterested in the pedestrians and bike riders go by. Another clip shows Emily pushed up against a parked silver van with her arms around Harry's neck, the singer planted in front of her, confidently stroking her hip and backside as he presses his lips to hers. In yet more footage, Emily writhes as loud music fills the air, beckoning Harry to join her as she dances in the street.

There's no denying it: Harry and Emily are hooking up. "It's definitely on," a source tells In Touch. Four months after Harry, 29, split from actress-director Olivia Wilde, 39, following nearly two years together, he's moved on with Emily, 31, who's been on a dating tear since leaving her husband of four years, Sebastian Bear-McClard, last summer amid claims the film producer had cheated on her. "Harry is notorious for being obsessed with his privacy and usually does whatever he can to ensure nobody finds out what he's up to," says the source. "But he couldn't help himself with Emily and let his guard down" while spending time with her during the Japanese leg of his Love On Tour. "They're hot and heavy and really enjoying themselves."

IT'S COMPLICATED