Klaus will be inhabiting the body of Tyler when The Vampire Diaries Season 4 kicks off on October 11. That could cause quite the problem for Caroline.

But a new reveal by producer Julie Plec makes it clear that the couple affectionately known as Forwood may have an issues beyond mere body/personality deception.

A blast from Tyler's past is coming to Mystic Falls.

Look for a young woman to arrive early on this fall, someone who shares a "history" with Tyler, Plec tells TV Line.

“We’ll start to understand that this is a friend of his, who’s been very important to him in the past,” says Plec, confirming that she means enough to Tyler for Caroline to have cause for concern:

"Any time a hot, new girl comes to town, somebody’s got to be worried about something. But Tyler and Caroline have a really solid bond, a really solid relationship. So it takes somebody really special to get in the way of that.”

We presume the visitor in question is the rumored new character of Hayley. Not many details are known about her, nor has she been cast.

For a lot more from Plec, read the full interview now. Then, visit our Vampire Diaries forum and have at it, fans!

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.