Armie Hammer is an American actor. After appearing on television and playing the title role in 2008's Billy: The Early Years, he became known for his portrayal of the Winklevoss twins in the 2010 film The Social Network. His upcoming movie roles include Clyde Tolson in J. Edgar, The Lone Ranger in a 2012 remake, and Prince Albert Alcott in Tarsem Singh's Snow White.

Hammer was born in Los Angeles, California. His mother, Dru Ann (née Mobley), is a former bank loan officer, and his father, Michael Armand Hammer, owns several businesses, including Knoedler Publishing and Armand Hammer Productions (a film/television production company). His paternal great-grandfather was oil tycoon and philanthropist Armand Hammer, and his great-great-grandfather, Julius Hammer, who immigrated from Odessa, "founded the Communist Party in New York". His mother's family is from Tulsa, Oklahoma. Hammer has described his background as "half Jewish".

Hammer lived in the prominent Dallas enclave of Highland Park, for several years. His family moved to the Cayman Islands when he was seven and to Los Angeles when he was eleven. He attended Faulkner's Academy in Governor's Harbour, Grace Christian Academy in the Cayman Islands (a school founded by his father), and later went to Los Angeles Baptist High School in the San Fernando Valley. He attended Pasadena City College in Pasadena, California, and went on to transfer to the University of California, Los Angeles, dropping out to pursue a career in acting.

Hammer married television personality Elizabeth Chambers; the two met at a West Hollywood gas station.

Hammer has appeared in the television series Arrested Development, Veronica Mars, Gossip Girl, Reaper, and Desperate Housewives. Hammer played the Christian evangelist Billy Graham in Billy: The Early Years, which premiered in October 2008. The film garnered Hammer a “Faith and Values Award” nomination in the Grace Award category, which is awarded for the Most Inspiring Performance in Movie or Television. He played Harrison Bergeron in 2081, based on the short story "Harrison Bergeron" by author Kurt Vonnegut, which premiered at the Seattle International Film Festival.

Hammer was hand-picked by filmmaker George Miller after a long search to star in Justice League: Mortal as Batman/Bruce Wayne. The film was to be directed by Miller, but he left the project.

In 2010, Hammer co-starred in David Fincher's The Social Network, about the creation of Facebook. He portrayed the identical twins Cameron and Tyler Winklevoss, with Josh Pence, using CGI. Hammer stated that he had to learn how to row on both sides of a boat in order to play the twins, who are rowing champions. His next role will be in Clint Eastwood's J. Edgar, a drama about J. Edgar Hoover. He will also co-star with Julia Robertsand Lily Collins in Snow White, playing Prince Albert Alcott, rather than the traditional Prince Charming. His other upcoming roles include playing The Lone Ranger, alongside Johnny Deppas Tonto, in an adaptation of the radio serial, and starring as an air traffic controller in the thriller 2:22.