Casting Scoops on 'House,' 'Supernatural,' 'Gossip Girl,' and 'SVU'

Just in time for the weekend, it’s a special TGIF edition of Casting Scoops!

* If Dean thinks Hell is hell, wait till he sees what’s waiting for him back on Earth this season: Supernatural has cast The Wire‘s Robert Wisdom in the recurring role of Uriel, a dangerous, intimidating, aloof, imperious, contemptuous, humorless killer. Sounds like a real peach, huh?

* House has admitted Samantha Shelton (Monarch Cove) to play a fitness instructor who comes down with a (brace yourself!) stupefying illness in a November episode.

* Wallace Shawn (The Princess Bride, Clueless) is joining Gossip Girl for a multi-episode arc as Cyrus, father to Serena’s new artsy-fartsy boyfriend Aaron (John Patrick Amedori). If Team Schwavage follows the Gossip Girl books, Cyrus will eventually marry Blair’s mother, Eleanor. Here’s hoping they follow the books, ’cause the thought of Wallace Shawn as Blair’s stepdad is hilarious with a capital HIGH.

* Martin Mull will guest-star on the Oct. 28 episode of Law & Order: SVU as a doctor. An SVU insider calls it “a big Tamara Tunie episode,” which is typically code for “Chris Meloni and Mariska Hargitay had the week off!”