From 2010 to 2017, "Pretty Little Liars" reigned on ABC Family/Freeform as one of the most popular teen dramas. The series, which starred Troian Bellisario, Ashley Benson, Lucy Hale, and Shay Mitchell, kept fans entertained with shocking moments, plot twists, and love triangles. The show even spawned a spinoff, called "The Perfectionists," which will premiere on Wednesday and introduce new characters. Throughout "PLL's" seven-season run, the fictional town of Rosewood was visited by several recognizable faces. This includes singers like Adam Lambert and actors like Rumer Willis.Here are 17 celebrities you probably forgot guest-starred on "Pretty Little Liars.""Dumplin'" star Danielle Macdonald appeared on season five as an animal shelter employee named Cathy.Cathy visited the DiLaurentis house with a dog that Jessica wanted to adopt.On season three, singer Adam Lambert performed during a Halloween party.He wore a pair of fake teeth to complete his vampire costume and had a brief conversation with Aria."The Gifted" star Emma Dumont played Katherine Daly, the daughter of the Senator of New York.She was interested in wearing one of Hanna's designs to a fundraiser.See the rest of the story at Business Insider Click here to read full news..