How I Met Your Mother is reuniting Willow and Oz!

Seth Green — who, of course, played Alyson Hannigan’s werewolf boyfriend on Buffy the Vampire Slayer — will guest-star on an upcoming Season 8 episode of the CBS sitcom, TVLine has confirmed.

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Even better news: His storyline will find him crossing paths with his former castmate! Green’s character Daryl LaCoutre considered Lily (Hannigan) and Marshall (Jason Segel) his best friends in college. However, they barely remember the guy. Despite the discrepancy, Daryl is still living in their college town and is creepily obsessed with having the new parents in his life.

The episode is tentatively slated to air Dec. 10.

Green — whose credits also include Robot Chicken and Family Guy — is the latest in a long line of Joss Whedon show alumni to visit the hit comedy. Past guests include Amy Acker (Angel, Dollhouse), Tom Lenk (Buffy), Morena Baccarin (Firefly), Harry Groener (Buffy), Alexis Denisof (Buffy, Angel) and Danny Strong (Buffy).

The casting was first reported by the show’s official Twitter account.