Mary Elizabeth Winstead (born November 28, 1984) is an American actress and singer. She's best known for her movie roles as Helena Bertinelli / Huntress in Birds of Prey (2020), John McClane's daughter Lucy Gennero-McClane in Live Free or Die Hard (2007) and A Good Day to Die Hard (2013), Holly Keely in The Spectacular Now (2013), Mary Todd Lincoln in Abraham Lincoln: Vampire Hunter (2012), and Ramona Flowers in Scott Pilgrim vs. the World (2010). Her best known TV roles are as Anna Urbanova on the Paramount+ series A Gentleman in Moscow, Laurel Healy on CBS's BrainDead, Mary Phinney on PBS's Mercy Street, and Nikki Swango on the FX series Fargo.

In 2010, she married filmmaker Riley Stearns, whom she had met at age eighteen on an ocean cruise. She starred in and produced Stearns's debut feature film, Faults, in 2014. She announced their separation in May 2017 and their divorce was finalized later that year.