In 2005, Tennant got to fulfill a childhood dream when he became the Tenth Doctor on BBC's newly-revamped Doctor Who television series. Tennant replaced Christopher Eccleston, a.k.a. the Ninth Doctor and went on to play the Doctor for nearly 50 episodes. Whovians were quickly won over by his boundless charisma, impeccable comedic-timing and flare for drama and consider him to be the quintessential Doctor.
Last year, the Shakespearan-trained actor shed his good-guy image and played Killgrave, a despicable mind-controller, in Marvel's Jessica Jones opposite Krysten Ritter.
Tennant is also known for his roles in Fright Night and Harry Potter & The Goblet of Fire as well as voicing Spitelout in How To Train Your Dragon and Fugitoid in Teenage Mutant Ninja Turtles.
Happy Birthday, David Tennant!