HBO has renewed its fantasy series "Game of Thrones" for a second season.

Enjoying a healthy premiere, the pilot episode pulled in 4.2 million viewers over three airings Sunday. "Game of Thrones" scored 2.2 million viewers during its 9 p.m. debut, 1.2 million for the second airing and 800,000 for the final encore.

“We are delighted by the way David Benioff and D.B. Weiss have brought George R.R. Martin’s amazing book series to the screen, and thrilled by the support of the media and our viewers,” said Michael Lombardo, president, HBO programming. “This is the continuation of an exciting creative partnership.”

Richard Plepler, HBO'S executive vice president, sees "Game of Thrones" as a quintessential show for the network.

"It has a passionate connection with a big part of our audience," Plepler explained in an interview with Entertainment Weekly. "Whether the final number is 7 or 8 million viewers it doesn’t take anything away from the addictive quality of the show for a large chunk of our audience."

Featuring a strong adult tone reminiscent of "Deadwood" and "The Sopranos," "Game of Thrones" chronicles a treacherous clash among royal families to secure ultimate power of Westeros, a vast kingdom where life is often fraught with peril and shockingly short.

"It’s a great show that only gets better with every episode and ends where you’re left wanting more," Lombardo said. "On a creative level, it was screaming for another season.

"We had absolutely expectation that this would be a slow build. It’s challenging for people who’ve decided it’s not a genre for them. The word of mouth has been great and we don’t even have OnDemand numbers yet. We thought it was a great starting place."

HBO also gave its audience additional opportunities to catch the series Monday, including encores on HBO, HBO2, HBO Signature, HBO Comedy, HBO Zone and HBO Latino. Rating results for that night are expected tomorrow.

Some of the key members of the show's large ensemble cast include Sean Bean ("The Lord of the Rings") as Eddard "Ned" Stark; Lena Headey ("Terminator: The Sarah Connor Chronicles," "300"), as queen Cersei Lannister; Peter Dinklage ("Threshold") as her cunning dwarf brother Tyrion; Nikolaj Coster-Waldau ("New Amsterdam") as Cersei's twin, Jaime; Emilia Clarke as the exiled queen Daenerys Targaryen; Michelle Fairley as Catelyn Stark; Jason Momoa ("Stargate: Atlantis") as Khal Drogo.

The series is executive produced by Benioff ("Troy," "The Kite Runner") and Weiss.

See our review of the pilot episode "Winter is Coming" here.