<Dd> Played by Aisha Kabia; appears in "Ted Mosby: Architect" and "World's Greatest Couple". Marshall's friend from law school and Brad's old girlfriend . </Dd> <Dd> Played by Laura Prepon; appears in 3 episodes from "Sorry, Bro" to "Say Cheese", as well as being mentioned in several others . Ted's first real girlfriend, Karen is depicted as highly sarcastic and snooty, which results in Marshall and Lily loathing her . The feeling is mutual, as Karen also has a low opinion of Ted's friends . Karen enjoys berets, Bordeaux wine and Baudelaire's erotic poetry . While Ted is deeply in love with her, Karen cheats on him every time she wants to break up . Karen is often described by critics as "Ted's worst girlfriend". </Dd> <Dd> Played by Lucy Hale; appears in 4 episodes from "First Time in New York" to "The End of the Aisle". Katie visits Robin (her sister) in New York and Robin reacts badly when she discovers Katie is planning to lose her virginity to a boy named Kyle . Bustle ranked her second in a list of best guest stars in the series . </Dd> <Dd> Played by Thomas Lennon; appears in "Farhampton" and "The Pre-Nup". Klaus is Victoria's fiancé . They were classmates at Victoria's culinary fellowship in Germany but enter a relationship roughly a day after Ted and Victoria break up . He appears on - screen in "Farhampton" as Victoria's groom, but both of them get cold feet at their wedding . The failure of the wedding sends Klaus into a spiral and he briefly stays at Ted's apartment . </Dd>

Who plays katie in how i met your mother