Sarah Paulson acts.
Sarah Catharine Paulson ( born December 17 , 1974 ) is an American actress . Paulson starred as Mary Epps in the 2013 historical drama film 12 Years a Slave and as Abby Gerhard in the 2015 drama film Carol . In 2016 , Paulson portrayed real life prosecutor Marcia Clark in the first season of the anthology series American Crime Story , subtitled The People v. O. J. Simpson .