Here are five facts about Stephanie:
She's following her big brother Spencer Pratt and sister-in-law Heidi Montag in appearing in the CBB house. Fellow Hills stars Spencer and Heidi were among the housemates on the 11th series in January 2013.
The Los Angeles native's first experience of fame was on The Hills, an MTV show that documented the lives of four glamorous girls - Lauren Conrad, Whitney Port, Heidi Montag and Audrina Patridge.
Stephanie isn't afraid to bare all, posing nude for PETA in 2010.
She may be a California girl, but she's spent plenty of time on our shores. She joined E4 reality show Made In Chelsea for its sixth series in 2013, where she romanced ladies' man Spencer Pratt.
Stephanie has openly spoken about her struggle with bulimia in the past, suggesting she felt pressure to stay thin while on The Hills and surrounded by beautiful women.
Celebrity Big Brother lineup:
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