Matthew Robert Smith (born 28 October 1982) is an English stage and television actor. He is known for his role as the eleventh incarnation of the Doctor in the British television series Doctor Who, for which he received a BAFTA Award nomination in 2011. He initially aspired to be a professional footballer, but a back injury forced him out of the sport. After joining the National Youth Theatre and studying Drama and Creative Writing at the University of East Anglia, Smith became an actor in 2003, performing in plays like Murder in the Cathedral, Fresh Kills, The History Boys and On the Shore of the Wide World in London theatres. Extending his repertoire into West End theatre, he has since performed in the stage adaptation of Swimming with Sharks with Christian Slater, followed a year later by a critically acclaimed performance as Henry in That Face. Before his role in Doctor Who, Smith's first television role came in 2006 as Jim Taylor in the BBC adaptations of Phillip Pullman's The Ruby in the Smoke and The Shadow in the North while his first major role in television came as Danny in the 2007 BBC series Party Animals. Smith, who was cast as the eleventh incarnation of the Doctor in January 2009, is the youngest person to play the character in the British television series. He has most recently appeared in the 2011 BBC television film Christopher and His Kind playing Christopher Isherwood. Description above from the Wikipedia article Matt Smith (actor), licensed under CC-BY-SA, full list of contributors on Wikipedia

Matt Smith plays as Prince Daemon Targaryen in House of the Dragon.
Matt Smith is the top #1 member of the cast and appears in 8 episodes.

Emma D'Arcy plays as Princess Rhaenyra Targaryen in House of the Dragon.
Emma D'Arcy is the top #2 member of the cast and appears in 8 episodes.

Patrick "Paddy" George Considine (born 5 September 1973) is an English actor, director, screenwriter and frequent collaborator with Shane Meadows. His directorial debut, the short film Dog Altogether, won a number of awards including the 2008 BAFTA Award for Best Short Film. Description above from the Wikipedia article Paddy Considine, licensed under CC-BY-SA, full list of contributors on Wikipedia.

Paddy Considine plays as King Viserys I Targaryen in House of the Dragon.
Paddy Considine is the top #3 member of the cast and appears in 8 episodes.

Olivia Kate Cooke (born 27 December 1993) is an English actress. She is known for her starring role as Emma Decody in the A&E drama thriller series Bates Motel (2013–2017) and as Becky Sharp in the period drama miniseries Vanity Fair (2018). She also starred in the horror film Ouija (2014), the comedy-drama film Me and Earl and the Dying Girl (2015), the period horror mystery film The Limehouse Golem (2016), the thriller film Thoroughbreds (2017), the sci-fi film Ready Player One (2018), and the drama film Sound of Metal (2020).

Olivia Cooke plays as Alicent Hightower in House of the Dragon.
Olivia Cooke is the top #4 member of the cast and appears in 8 episodes.

Rhys Ifans (born Rhys Owain Evans; 22 July 1967) is a Welsh actor and musician. He was the frontman of Welsh rock music bands the Peth and Super Furry Animals. As an actor, he is best known for his roles in Notting Hill (1999), Kevin & Perry Go Large (2000) and Enduring Love (2004) as well as his portrayals of Xenophilius Lovegood in Harry Potter and the Deathly Hallows – Part 1 (2010), the supervillain Lizard in The Amazing Spider-Man (2012) and Spider-Man: No Way Home (2021), and Grigori Rasputin in The King's Man (2021). Other roles include Hector DeJean in the Epix thriller series Berlin Station, Mycroft Holmes in the CBS series Elementary, and Ser Otto Hightower in the HBO television series House of the Dragon.

Rhys Ifans plays as Ser Otto Hightower in House of the Dragon.
Rhys Ifans is the top #5 member of the cast and appears in 8 episodes.