According to Woman's Day Australia (who can "exclusively reveal" the news), Harry heard about Watson's split from British rugby player Matthew Janney and got some mutual friends to help him woo her. He invited her to a small party among friends, because ugh, dates are just so formal.
Source: marieclaire In Emma Watson's response to this rumor: The world finally heard from Watson when she tweeted a strong indication that the rumors were not to be believed.