Viggo Peter Mortensen, Jr. (Danish: [viɡ̊o ˈmɒːdnsn]; October 20, 1958) is an American actor, poet, musician, photographer and painter. He made his film debut in Peter Weir's 1985 thriller Witness, and subsequently appeared in many notable films of the 1990s, including The Indian Runner (1991), Carlito's Way (1993), Crimson Tide (1995), Daylight (1996), The Portrait of a Lady (1996), G.I. Jane (1997), A Perfect Murder (1998), A Walk on the Moon (1999) and 28 Days (2000).

Mortensen grew in prominence in the early 2000s with his role as Aragorn in the epic film trilogy The Lord of the Rings. In 2005, Mortensen won critical acclaim for David Cronenberg's crime thriller A History of Violence. Two years later, another Cronenberg film Eastern Promises (2007) earned him further critical acclaim and an Academy Award nomination for Best Actor in a Leading Role. A third teaming with Cronenberg in A Dangerous Method (2011) resulted in a Golden Globe Best Supporting Actor nomination. Other well-received films in recent years have included Appaloosa (2008) and the 2009 film adaptation of Cormac McCarthy's novel The Road.