How I Met Your Mother Season Finale Mystery: Is Happy Endings' Casey Wilson You-Know-Who?!

How I Met Your Mother Season 8 Spoilers Casey WilsonHow I Met Your Mother has landed a simply a-mah-zing guest star.

Happy EndingsCasey Wilson has signed on to appear in the CBS comedy’s May 13 season finale, TVLine has confirmed.

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According to Vulture, which first broke the news, Wilson and Key and Peele‘s Keegan-Michael Key will play a couple having dinner at the same restaurant as bride and groom-to-be Robin and Barney.

What does it mean? Could Wilson be The One? Is this much ado about nothing beyond a fun one-off appearance? Theories below, please!