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Peter Dinklage spent decades in the industry before he became Tyrion Lannister. The New Jersey-born actor made his big-screen debut in 1995's Living in Oblivion, playing an actor named Tito (pictured here) who is tired of being typecast. He continued to rack up small roles before rising to fame in the 2000s.
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Years before he became the famed Joffrey Baratheon, Jack Gleeson hit the big screen as an unnamed little boy in 2005's Batman Begins.
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Lena Headey booked her first on-screen role as a teenager. The star, who would later become Cersei Lannister on Game of Thrones, debuted in 1992's Waterland, playing the young counterpart to Sinéad Cusack's character of Mary.
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A relative newbie, Emilia Clarke got her start in smaller projects like TV movies and short films. One such endeavor was 2010's Triassic Attack on Syfy, in which she played a small role.
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In the mid-2000s, a then-unknown actor by the name of Kit Harington joined a production of War Horse in London. He would go on to earn his first on-screen credit in 2011 as Jon Snow on Game of Thrones.
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Isaac Hempstead Wright
At just 12 years old, Isaac Hempstead Wright made his big-screen debut in 2011's The Awakening, beginning his turn as Bran Stark the same year.
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Decades before he took on the role of Ser Jorah Mormont, Iain Glen earned his first big-screen credit in 1988's Paris By Night, a British thriller which never made it to theaters stateside.
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Nikolaj Coster Waldau
In his mid-20s, a young Nikolaj Coster Waldau made his feature film debut in the Danish thriller Nightwatch (1994). He played Martin, the night watchman in question, more than 20 years before he would become Jaime Lannister.
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Before he rose to fame thanks to his Game of Thrones role of Samwell Tarly, John Bradley-West appeared in a handful of episodes of the European drama Borgia.
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A decade before he joined Game of Thrones as Theon Greyjoy, Alfie Allen found himself in the presence of thrones in 1998's Elizabeth. He played a small part in the Oscar-winning film.
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Irish actor Aidan Gillen, who now plays Petyr Baelish in Game of Thrones, once held a supporting role in 1995's Circle of Friends, which starred Chris O'Donnell and Minnie Driver, among others.
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Jerome Flynn picked up one of his first on-screen roles in the late '80s. He played Joe Narracombe in the British drama A Summer Story, a change of pace from his GoT character of Bronn.
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Irish actor Liam Cunningham started acting in the '90s. The Davos Seaworth appeared in 1995's A Little Princess.
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Conleth Hill, who plays Varys, picked up an early role in the British sitcom Blue Heaven, starring in the show for its short-lived run.
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Gwendoline Christie may be famous for playing Brienne of Tarth in Game of Thrones, but she first earned acting credits in the 2000s. One of her first roles was that of the so-called "Classy Shopper 2" in 2009's The Imaginarium of Doctor Parnassus.