Laura Prepon ( born March 7 , 1980 ) is an American actress , best known for her role as Donna Pinciotti on the Fox television series That '70s Show and Hannah Daniels on the ABC television series October Road . Laura Prepon ( pronounced pree-pawn , born March 7 , 1980 ) is an American actress , best known for her role as Donna Pinciotti in the long-running Fox situation comedy That '70s Show , for all eight seasons . She is also known for the role of Hannah Daniels on the ABC drama October Road .