Eddie McClintock

Castle and Beckett's nuptials may have just gotten a little more complicated.

Eddie McClintock has been tapped to guest-star in "For Better or Worse," the upcoming season finale of Castle, TVGuide.com has confirmed.

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The Warehouse 13 alum, whose credits also include Modern Family and The Mentalist, will play small town hustler Rogan O'Leary who shares a complicated past with Beckett (Stana Katic), according to TVLine. Could he play spolier at the (presumed) wedding?

McClintock first announced his casting on Instagam

Castle airs Mondays at 10/9c on ABC.