David Thewlis (born David Wheeler; born 20 March 1963) is an English actor, director, screenwriter, and author. He first rose to promience for playing Johnny Fletched in the film Naked (1993), for which he won the Cannes Film Festival Award for Best Actor. His most commercially successful roles to date have been of Remus Lupin in the Harry Potter film series and Ares in Wonder Woman (2017). Other notable film appearances include Dragonheart (1996), Seven Years in Tibet (1997), Kingdom of Heaven (2005), The Boy in the Striped Pyjamas (2008), War Horse (2011), The Theory of Everything (2014) and Anomalisa (2015).

Thewlis has combined major motion picture work with prominent television roles, including portraying Cyrus Crabb in the ABC miniseries Dinotopia (2002) and V. M. Varga in the third season of Fargo (2017).