The 27-year-old "Thirteen" star will play the key series regular role of Betsy Ross on the upcoming season on Fox, said The Hollywood Reporter.
"We are all very excited to welcome Nikki Reed into the world of 'Sleepy Hollow'. Nikki's the perfect choice to bring a smart and sexy edge to our show's twisted version of American icon, Betsy Ross," co-creator/EP Len Wiseman said.
Reed will essay the character of Ross, a famous seamstress known and loved for sewing the nation's first flag by day and a dynamic colonial insider by night.
The upcoming season will be shot in Atlanta, where Reed's new husband, Ian Somerhalder, films "The Vampire Diaries."
"Sleepy Hollow" season 3 will premiere on October 1 on Fox.