If 'How I Met Your Mother' plans to follow through on its intent of setting most of the ninth and final season and Barney and Robin's wedding weekend, you'd better believe the guest list will be star-studded. The latest to join the 'HIMYM' gang's final season is none other than former 'The Office' darling Ellie Kemper, but who's head will she be turning?

According to TVLine, who first reported the news, Kemper will take the role of Cassie, described by producers and co-creators Carter Bays and Craig Thomas as “one of the most attractive, available, and — as Ted discovers — unfortunate guests at Barney and Robin’s wedding."

For now only set to appear in a single episode of the final season, Kemper joins fellow season 9 guest stars Sherri Shepherd as a woman on Marshall's flight, and Wayne Brady reprising his role as Barney’s half-brother James Stinson for a recurring role in the long-running CBS comedy’s ultimate year

While we expect to learn more from this week's first (and last) appearance at Comic-Con 2013, we know that season 9 will take place largely across the 56-hour period leading up to Barney and Robin’s wedding, at which Ted finally meets his bride-to-be. The network also revealed that all four regulars would meet the mother (herself a newly-minted regular) prior to Ted, while individual episodes may cut back and forth through time as necessary to tell the complete story.

Well, what say you? Are you excited to see 'How I Met Your Mother' stock up on final season cast with such a familiar face? What do you think will happen between Ted and Ellie Kemper's character?

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