I know it's been 9 years, but...
[Taken from Esquire Magazine]

And what about all those hormone-fuelled teenagers running around on a film set? "There was a period when we were the only boys and girls any of us knew. And so, u know, we were all unbelievably horny from about the third film to probably about the end of the fifth; then it all settled down. But, God, for a few years..."

Despite an early debilitating crush on a production hair stylist [...] he also denies any on-set transgressions. "There was never anybody I fancied that much in the cast, though the conspiracy theorists always like to say that I and Emma are dating." Surely they were the obvious match-up? "Even if we were that much in love with each other, I don’t think we could beer to give the press the story. We know it'd be everything the fans ever wanted. I’m sorry guys, it’s not happening. It’s just not. There’s something really incestuous about the idea of it."

"Still, he'll say that he had his first girlfriend at 14, whom he met through his co-star Watson (who plays hot swot, Hermione Granger)