'How I Met Your Mother' Taps Casey Wilson for Season Finale

The "Happy Endings" star joins Keegan-Michael Key on the CBS comedy; maternal identity speculation ensues.
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How I Met Your Mother is welcoming guests from two other comedies for its upcoming season eight finale.

A studio rep confirms to The Hollywood Reporter that Happy Endings' Casey Wilson and Key and Peele's Keegan-Michael Key are both set to appear, as first reported by Vulture.

News of Wilson's addition prompts obligatory speculation about the CBS comedy's yet-to-be-identified "mother," but, at the moment, it seems she and Key will just be playing dining partners at the same restaurant as Barney (Neil Patrick Harris) and Robin (Cobie Smulders).

In addition to his Comedy Central series, Key recently was cast in Lennon Parham and Jessica St. Clair's USA pilot. Wilson, whose Happy Endings has been off the schedule at ABC since January, returns with her series Friday, March 29.