Heidi and Spencer Will Guest Star on How I Met Your Mother
Montag, 22, and Pratt, 25, will guest star on an episode of the CBS sitcom How I Met York Mother that will air in January. Both will film their segments this week.
"We can confirm that Heidi and Spencer will appear on the show," co-creator and executive producer Craig Thomas tells PEOPLE, "but we can't give away anything specific about the episode. All we can say is that they play themselves, and one of them is The Mother."
Montag and Spencer join an impressive line of guest stars on How I Met Your Mother, including Britney Spears, James Van Der Beek, Heidi Klum, and Mandy Moore.
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