David Tennant (born David John McDonald; 18 April 1971) is a Scottish actor. In addition to his work in the theatre, Tennant is best known for his roles in Doctor Who as the tenth incarnation of the Doctor, in Casanova as the title character, and as Barty Crouch, Jr. in Harry Potter and the Goblet of Fire.

Tennant was born David John McDonald on 18 April 1971 in Bathgate, West Lothian and grew up in Ralston, Renfrewshire, where his father (the Reverend Alexander ("Sandy") McDonald) was the local Church of Scotland minister (and Moderator of the General Assembly of the Church of Scotland in 1997). Tennant was educated at Ralston Primary and Paisley Grammar School where he enjoyed a fruitful relationship with English teacher Moira Robertson, who was among the first to recognise his potential. He then earned a bachelor's degree from the Royal Scottish Academy of Music and Drama, where he was friends with Louise Delamere.

At the age of three, Tennant told his parents that he wanted to become an actor because he was a fan of Doctor Who. Although such an aspiration might have been common for any British child of the 1970s, Tennant says he was "absurdly single-minded" in pursuing his goal. He adopted the professional name "Tennant" — inspired by Neil Tennant of the Pet Shop Boys, after reading a copy of Smash Hits magazine — because there was another David McDonald already on the books of the Equity union. His second choice for a stage name was David Brandon and his third choice was Chris McDonald.