'Castle' Books Eddie McClintock in Complicated Role for Season Finale

Believe it or not, there's only a handful of episodes left until 'Castle's Season 6 finale. So, naturally, details of that pivotal night are starting to be unleashed. For example, TVLine has exclusively learned that the series has hired 'Warehouse 13's Eddie McClintock for a very interesting role.

The actor — who confirmed the exciting casting news on his Instagram account (see photo below) — will appear in the May 12 season ender, titled “For Better or Worse,” as Rogan O’Leary, a small town hustler who is infamous for his lying, cheating and scheming.

So what makes his character so different from every other bad guy this show has faced? He also supposedly has a very complicated past with none other than Kate Beckett. Thus far, ABC is keeping pretty tight-lipped about revealing any further information — like what exactly their relationship entails. Was it of a romantic nature or something much more mysterious?

Either way, we're sure it's going to mean bad news for our favorite crime-fighting duo. Dare we say, this could spell out catastrophe for the Castle-Beckett wedding? Fingers crossed that won't be the case.

In addition to his five-season run on 'Warehouse 13' (which debuts its final season on April 14), McClintock’s previous TV credits also include arcs on 'Bones' and 'My Boys' as well as guest-starring gigs on 'Modern Family,' 'Malibu Country' and 'The Mentalist.'

'Castle' airs Mondays at 10/9c on ABC.