"Game of Thrones" was a launching pad for a number of stars like Kit Harington and Emilia Clarke.
We've rounded up what 27 of the show's actors were doing before they were cast by HBO.
As a drama school student, Kit Harington landed the role of Albert in the National Theatre's adaptation of "War Horse," a role he reprised on the West End.
Casting director Nina Gold first spotted Harington when he was starring in a 2009 London production of "War Horse." She brought him in for an audition, and the rest was history.
"I remember that he was quite tired, because he'd been doing eight shows a week in 'Warhorse' for a year," Gold told Insider in a 2017 interview. "Then he started doing the audition and playing Jon Snow and he was completely brilliant. I do recall the emotional impact of his audition and being blown away. Kit is a phenomenal actor."
Peter Dinklage made his film debut in 1995, but his breakout role came in 2003's "The Station Agent."
"The Station Agent" was directed by Tom McCarthy — the same man who directed the first version of the "Game of Thrones" pilot.
Dinklage also appeared in 2003's holiday movie "Elf."
Isaac Hempstead Wright made his film debut in "The Awakening" the same year he began playing Bran Stark.
Hempstead Wright was just about 11 years old when he was cast as Bran Stark in "Game of Thrones." He had been acting in a small UK theater company when he was scouted for the HBO series.
Emilia Clarke's two professional onscreen roles before being cast as Daenerys Targaryen were on an episode of the British soap "Doctors" and Syfy's "Triassic Attack."
During a 2018 acceptance speech at the British Academy Britannia Awards, Clarke also said that her "biggest job" before the HBO series was "catering parties dressed as Snow White."
Nikolaj Coster-Waldau starred in numerous Danish films and TV shows before making his US debut as Gary Gordon in 2001's "Black Hawk Down."
His portrayal of Jaime Lannister has introduced the Danish actor to a wider audience.
Before playing Arya Stark, Maisie Williams had never acted professionally.
Since then, the 24-year-old has added more credits to her name, including four episodes of "Doctor Who" and five feature films.
Sophie Turner also made her acting debut on "Game of Thrones," with the role of Sansa Stark.
Turner told the Hollywood Reporter that she got the role of the eldest Stark sister when a casting call reached her local middle school. She was taking acting as an elective class, and auditioned without even telling her parents.
Since then, Turner has appeared in a number of films, including "X-Men: Apocalypse."
Lena Headey made her feature film debut in "Waterland" in 1992, almost 20 years before the premiere of "Game of Thrones."
She went on to appear in films such as "300," and portrayed Sarah Connor in Fox's "The Sarah Connor Chronicles" before landing the role of Cersei Lannister.
Jonathan Pryce plays the despised High Sparrow in "Game of Thrones," but his prolific career has taken him from the stage (he's the winner of two Tony Awards) to TV and film roles.
Pryce had roles in "Barbarians at the Gate," the "Pirates of the Caribbean" franchise, and "G.I. Joe" before starring in the HBO series.
Alfie Allen made his debut in 1998 with the TV movies "You Are Here" and "Elizabeth," but didn't act again until 2004's "Agent Cody Banks 2."
Allen didn't act again until 2004's "Agent Cody Banks 2," and then was cast in "Game of Thrones" in 2010.
Gemma Whelan appeared on stage and in a number of TV shows and films, including "The Wolfman," before she was cast as Yara Greyjoy.
Whelan is a comedian and professional dancer, and has since appeared in other TV hits like Netflix's "The End of the Fxxxing World."
Aiden Gillen starred in a number of roles before receiving critical acclaim for his role in the 1999 British series "Queer as Folk."
Fans may also recognize the actor, who played Petyr Baelish (Littlefinger), from HBO's "The Wire."
Natalie Dormer made her film debut in 2005's "Casanova."
The actress, who plays Margaery Tyrell, is also well-known for portraying Anne Boleyn in "The Tudors."
Liam Cunningham made his film debut in 1992 and has appeared in films such as "A Little Princess," "Dog Soldiers," and "Clash of the Titans."
He starred as Ser Davos Seaworth in "Game of Thrones" from seasons two through eight.
Gwendoline Christie began her career on stage in 2006, and made her film debut as a shopper in 2009's "The Imaginarium of Doctor Parnassus."
Christie's portrayal as Brienne of Tarth on "Game of Thrones" was her first major role.
Kristofer Hivju acted in numerous Norwegian films and 2013's "After Earth" before he was known as Tormund Giantsbane in "Game of Thrones."
His career has continued to grow, and he's now part of other major franchises like the "Fast and Furious" films and "Justice League."
Though well-known for the "Resident Evil" films, Iain Glen made his acting debut in an episode of Scottish detective drama "Taggart."
His feature film debut was in 1988's "Paris by Night" (as seen above). Glen played Ser Jorah Mormont throughout all eight seasons of "Game of Thrones."
Carice van Houten's first notable role was in the TV film "Suzy Q."
She went on to star in "Black Book," "Valkyrie," and "Repo Man" before being cast as Melisandre in "Game of Thrones." Van Houten also appeared in a number of Dutch films and TV series.
Michiel Huisman began his career in Dutch TV shows and films, even appearing alongside Carice van Houten in "Suzy Q" and "Black Book."
Huisman's break in the US came with a starring role as Sonny in HBO's "Treme." He replaced Ed Skrein as Daario Naharis in season four of "Game of Thrones."
Rory McCann appeared in projects including the Scottish dramedy "The Book Group," "Alexander," and "Hot Fuzz" before his time on HBO's hit series.
McCann played Sandor Clegane, aka "The Hound", in "Game of Thrones."
Indira Varma made her film debut in 1996's "Kama Sutra: A Tale of Love."
Her other credits include "Bride and Prejudice" and TV series "Luther." She played Ellaria Sand starting in the fourth season of "Game of Thrones."
Nathalie Emmanuel made her acting debut at the age of 10 in the West End production of "The Lion King."
Emmanuel went on to score her first on-screen role in the British soap "Hollyoaks." She's started on "Game of Thrones" in 2013 with the role of Missandei.
Iwan Rheon was 17 when he was cast in the Welsh-language soap "Pobol Y Cwm," but soon transitioned to the stage where he won an Olivier Award.
Rheon was cast as Moritz Stiefel in the London production of "Spring Awakening" and won an Olivier Award for his performance. Directly after that, he was cast in the TV series "Misfits," before becoming the loathsome villain Ramsay Bolton in "Game of Thrones."
Hannah Murray began her professional career in the British teen drama "Skins," along with a couple other "Game of Thrones" actors.
Murray played Gilly starting in season two of "Game of Thrones." Her former "Skins" costars, Jacob Anderson (Grey Worm) and Joe Dempsie (Gendry) also had roles in the HBO series.
Before playing Samwell Tarly on "Game of Thrones," John Bradley portrayed a cardinal on the historical TV drama "Borgia."
Bradley's character Sam was one of the few characters who survived all eight seasons of "Game of Thrones."
Before playing King Robert Baratheon, actor Mark Addy was best known for movies like "The Full Monty" and "A Knight's Tale."
Addy also appeared in the 2010 movie "Robin Hood," and in the 1998 holiday film "Jack Frost."
Most fantasy fans know Sean Bean starred in "The Lord of the Rings" before "Game of Thrones," but he was also in movies "National Treasure" and "Troy."
Bean played Odysseus in 2004's "Troy," the screenplay for which was written by "Game of Thrones" coshowrunner David Benioff.
To learn more about how the "Game of Thrones" pilot first came about with Benioff and his cocreator D.B. Weiss, read our deep dive into the show's creation here.
Angelica Oswald contributed to a previous version of this article.
Read the original article on Insider