Emma Watson. (AP Files)

Harry Potter star Emma Watson was left "quite shaken" after students from rival U.S. university Harvard stalked her during a recent football match.

The actress, who attends Brown University, Rhode Island, was at a game between the two schools on Saturday, but security guards had to surround her to protect her from harassment.

Harvard's student magazine The Voice targeted Watson and posted a blog on its website stating supporters would try to draw as much attention to her as possible.

The post reads, "We will be Live-Tweetin’ the game and possibly stalking Emma Watson, so keep your eyes peeled for that, too!”

During the match, students from the Harvard Voice wrote a series of posts on Twitter.com, including: "In enemy territory. Lookin for a certain witch,” and, “WATSON FOUND. I repeat WATSON FOUND.”

The magazine also posted a photo of the star and branded the stalking campaign a "success", according to New York gossip column PageSix.

But after a series of complaints, the editor of The Voice attached a note to the picture saying, "There seems to be much ado about nothing over this photo and liveblog. Understand that these live tweets were made to be intentionally outrageous and overblown.”

There was no comment from Watson's representative as WENN went to press. A spokesperson from Brown said, "This isn’t the sort of thing we comment on.”