Caitlin FitzGerald (born August 25, 1983) is an American actress and filmmaker. She is best known for her role as Libby Masters in the Showtime television drama Masters of Sex and as the elusive Simone in STARZ tv series Sweetbitter. FitzGerald was raised in Camden, Maine. Her father, Des FitzGerald, is the former CEO of the ContiSea unit of the multinational corporation ContiGroup and the founder of Ducktrap River Fish Farm Inc. Ben Brantley of The New York Times said of her performance: "All legs, eyes and cheekbones, with a face that seems made for cinematic close-ups, she’s a hypnotic pleasure to look at." However, he felt she had insufficient gravitas, often bringing to mind "a newly transferred, intimidatingly classy high school senior, perhaps, who is so beyond being merely popular"
FitzGerald starred in the Showtime period drama Masters of Sex. Indiewire has described her character as one of the most underrated in television: "Libby Masters is a character who could easily have come across as insipid instead of likable and poignant ... FitzGerald fully conveys Libby's willowy fragility, her fairly sheltered outlook and girlishness -- she sometimes calls her husband "Daddy"—while making it clear she isn't a simple stand-in for conservative values or cluelessness ... FitzGerald makes Libby's perceptiveness and her transparency clear." FitzGerald joined the cast of Robert Krzykowski's upcoming film The Man Who Killed Hitler and Then the Bigfoot in June 2017, co-starring with Sam Elliott and Aidan Turner. In 2015, she appeared in the indie comedy Adult Beginners (previously called Brother's Keeper) from director Ross Katz as Kat, the girlfriend of Jake (Nick Kroll) who dumps him after his tech startup fails and he moves back to his family home. Rose Byrne and Bobby Cannavale co-star.