Robin and Barney are making a slight tweak to their wedding guest list.

True Blood‘s Anna Camp has RSVP’d for How I Met Your Mother‘s highly anticipated nuptials playing a character originally earmarked for The Office‘s Ellie Kemper, TVLine has learned exclusively.

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The super-busy Camp assumes the role of Cassie, one of the most attractive, available, and — as Ted discovers — unfortunate guests at big event.

Kemper, whose initial casting was reported by TVLine back in July, had to bow out due to a scheduling conflict.

Camp is set to appear in one episode, but, given the wedding’s season-long structure, it’s possible she could return.

HIMYM‘s farewell season kicks off Sept. 23.