Exclusive: 'Castle' pairs Dana Delany with a Hero

Desperate Housewives‘ Dana Delany will have some backup when she crosses over to Castle later this season.

Ex-Heroes star Leonard Roberts has been cast as the partner of Delany’s kick-ass federal agent character, sources confirm to me exclusively.

In the two-part episode, the first of which is conveniently scheduled to air immediately following Housewives on March 21, the feds (a.k.a. Delany and Roberts) are brought in to assist Castle and Beckett on a serial killer case. The conclusion airs the following night in Castle‘s regular Monday-at-10 timeslot.

In related news, ABC — no doubt encouraged by Castle‘s season-high ratings on Monday — just increased the show’s episode order from 22 to 24.

It’s official: This thing’s a hit!

Image Credit: Delaney: Tina Gill/PR Photos; Roberts: Chris Hatcher/Photorazzi/PR Photos