Charisma Carpenter

Charisma Carpenter will guest-star on Blue Bloods this fall, TVGuide.com has confirmed.

The Buffy and Angel alum will play Marianne Romano, a former popular girl in high school, who is now flashy, overly needy and just too obvious for a guy with a touch of class.  Having had a fling with Danny (Donnie Wahlberg) a couple decades back, she calls on him for help when her bruiser-fiancée decks her in a fit of 'roid rage.  But her attempt to tweak Danny's heartstrings backfires when it results in a police investigation of her boyfriend.

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Carpenter first announced the news on Twitter Thursday. "Playing 'Marianne' on [Blue Bloods] is the most fun I have had [with] a character in a long time. Staten Island accent and a lot of leopard!"

Since her days in the Whedonverse, Carpenter has appeared on Supernatural, Greek and The Lying Game.

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Blue Bloods returns Friday at 10/9c on CBS. Carpenter's episode is slated for November.

(Full disclosure: TVGuide.com is owned by CBS.)