Just hours after early ratings showed this week's "Castle" hitting new series highs in all major demos, ABC has renewed the Monday night drama for a third season.
 
"Castle," which stars Nathan Fillion and Stana Katic, was considered a bubble renewal last spring after its first season. Airing after "The Bachelor" and "Dancing with the Stars" this season, the drama has shown increased retention from its lead-ins (leads-in?) in the Monday 10 p.m. slot.
 
Benefitting from an unexpectedly strong "Dancing with the Stars" premiere, plus a heavily arced two-parter, "Castle" has set series highs each of the past two weeks. Last week, "Castle" scored a rare victory over a new "CSI: Miami," while Monday's episode averaged nearly 14.5 million viewers in early estimates, adding a 3.7 demo rating.
 
The "Castle" renewal wasn't exactly a huge shock. ABC had already announced the release of "Naked Heat," sequel to the bestselling companion novel "Heat Wave," for a fall 2010 release. There wasn't going to be much logic to releasing a companion book to a cancelled series. 
 
In any case, there's no longer any doubt. "Castle" will be back on ABC next fall.