It's Really Happening, People: Here's Everyone Joining the Game of Thrones Prequel Cast

According to Variety, Watts has officially been tapped to star in the pilot. There isn't much known about her character, except for that she is playing "a charismatic socialite hiding a dark secret." Can't you see her nailing an icily complex character like Cersei?

Josh Whitehouse, who plays Hugh Armitage in Poldark, will star in some capacity. Although he isn't a household name quite yet, the series has proven adept at launching the careers of relatively unknown stars, like Maisie Williams, Sophie Turner, and Kit Harington.

Ackie is set to appear in Star Wars: Episode IX in December, and recently had a role in Yardie.

Henley made a name for herself by playing Lucy in The Chronicles of Narnia film franchise, and will play Meg Tudor in the upcoming TV series The Spanish Princess.

You'll likely recognize Bower for his work in the Twilight movies, as well as TNT's short-lived Will or AMC's The Prisoner.

Regbo had Reign fans swooning for a few seasons of The CW's historical drama, but most recently played Young Dumbledore in November's Fantastic Beasts: The Crimes of Grindewald.

The British actor has been in everything from To the Bone to How to Talk to Girls at Parties, and will appear in the upcoming comedy Nasty Women alongside Anne Hathaway and Rebel Wilson.

Jeremiah already has a link to Game of Thrones through Lena Headey and Iain Glen, who he'll star with in The Flood. If you want to get a taste of his work before that comes out, however, watch his guest spots in Doctor Who or his heartbreaking performance in AMC's Humans.

Atim won an Olivier Award for her role in Girl From the North Country and Othello, so you know she has the dramatic chops to pull off whatever the prequel throws at her.

Gough is also an Olivier Award winner, thanks to her performance in the play People, Places, and Things. You might also have seen her with Keira Knightley in Colette, and playing opposite Chris O'Dowd in Juliet, Naked.

You might have seen McCabe in Notting Hil, Collateral, and Vanity Fair.

Heffernan has a vast list of theatre credits, including appearances in The Crown and Collateral.

Marvel fans will recognize Rodriguez from Netflix's Luke Cage and Iron Fist.

Richardson is a familiar face for any Harry Potter fan, having played Rita Skeeter in Harry Potter and the Goblet of Fire and Harry Potter and the Deathly Hallows: Part 1. The Golden Globe and BAFTA-winner has also appeared in Sleepy Hollow, The Young Victoria, and The Phantom of the Opera.

Simm is another actor with credits from both the screen and stage, including appearances in Doctor Who, Collateral and Life on Mars.