As HBO announced the Season 3 premiere of "Game of Thrones" as March 31, 2013 during Comic-Con International in San Diego today, it also revealed a sizable number of cast additions.

Season 3 filming is already underway based on George R.R. Martin's novel "A Storm of Swords," with the production returning to lens in Belfast, Northern Ireland; Croatia, representing parts of King’s Landing; and Iceland.

Joining the cast's swelling ranks this year are:

--Ellie Kendirck as Meera Reed., whose family are important Stark allies.

--Thomas Brodie-Sangster as Jojen Reed, who has supernatural gifts and is the sister of Meera.

--Clive Russell ("Sherlock Holmes") as Bryndon “The Blackfish” Tully, the uncle of Catelyn Stark (Michelle Fairley).

--Tobias Menzies ("Casino Royale") as Edmure Tully, the younger brother of Catelyn . He is the Lord of Riverrun following the death of his father.

--Diana Rigg ("On Her Majesty's Secret Service") as Lady Olenna “The Queen of Thorns” Tyrell. She is the grandmother of Margaery (Natalie Dormer) and Loras Tyrell (Finn Jones).

--Richard Dormer as Beric Dondarrion, who was deployed with a group of knights by Ned Stark in Season 1. Later, with Stark dead, he became the leader a band of outlaws.

--Paul Kaye as Thoros of Myr, a Red Priest who rides with Dondarrion's raiders and is famous for flaunting a flaming sword.

--Philip McGinley as Anguy, a raider serving Dondarrion.

--Mackenzie Crook as Orell, a wildling raider with a special connection to animals.

--Kristofer Hivju as Tormund Giantsbane, a wildling warrior and commander in service of the “King Beyond the Wall,” Mance Rayder.

--Nathalie Emannuel as Missandei, a slave in the city of Astapor.

--Anton Lesser as Qyburn, who once served as a maester of the Citadel.

--Tara Fitzgerald as Selyse Baratheon, Stannis Baratheon's (Stephen Dillane) reclusive wife.

--Kerry Ingram as Shireen Baratheon, Stannis' only child.

View a video of the new cast introducing themselves here.

"Game of Thrones" chronicles a treacherous clash among royal families to secure ultimate power of Westeros, a vast kingdom facing peril at every corner.

The series was recently nominated nine times during the 2012 Airlock Alpha Portal Awards, including nods for Best Actor/Television (Peter Dinklage), Best Actress/Television (Lena Headey), Best Supporting Actor/Television (Aidan Gillen), Best Supporting Actress (Michelle Fairley), Best Supporting Actress (Maisie Williams), Best Young Actor (Maisie Williams), Best Young Actor (Jack Gleeson), Best Episode/Television ("Ghost of Harrenhal") and Best Series/Television. You can now participate in the voting here.

David Benioff ("Troy," "The Kite Runner") and D.B. Weiss executive produce the series along with Carolyn Strauss and Frank Doelger. Martin, Vanessa Taylor, Alan Taylor, Guymon Casady and Vince Gerardis co-executive produce the show, with Bernadette Caulfield serving as a producer.

"Game of Thrones" stars Dinklage, Headey, Nikolaj Coster-Waldau, Emilia Clarke, Fairley, Williams, Sophie Turner, Kit Harington.

The GenreNexus sites -- Airlock Alpha, Rabid Doll and Inside Blip -- are at Comic-Con International and its coverage is being brought to you exclusively by Roddenberry.com.