Ellis basically serves as a living Easter egg while portraying Swift's daughter-in-law Kimber, wearing a curly blond wig and the black dress from her 2009 "Fearless Tour." Known to "It's Always Sunny in Philadelphia" fans as the waitress whose name is never revealed, Ellis also played Nick Miller's ex-girlfriend Caroline in "New Girl" and has had recurring roles in "Santa Clarita Diet," "The Grinder," "Perfect Couples," and more.