Game Of Thrones has been commissioned for a fifth and sixth series, it has been announced.

The debut episode of the wildly popular fantasy drama's fourth season notched-up HBO's second-highest ratings ever for original programming when it aired on Sunday.

And although more series might have seemed inevitable, HBO has now made it official that fans will be able to visit Westeros for at least two more runs of the show.

The season currently airing on HBO Stateside and Sky Atlantic in the UK covers the events of George RR Martin's third book, A Storm of Swords - the first half of which made up the story of last season.

The entirety of the author's fantasy epic will take place over the course of seven books, meaning that the show has four seasons of story left at the very least.

However, one of the show's creators, David Benioff has previously indicated that he only sees the TV version of Martin's story continuing to the seventh or eighth seasons.

Meanwhile, if you were left wanting more after the season opener - a preview teaser has been released online for episode two.

It begins with the voice of Tyrion Lannister announcing: "A toast to the proud Lannister children - the cripple, the dwarf and the mother of madness."

Then Varys "The Spider" asks Tyrion: "Have you ever known your father to make an idle threat?"

And Bran Stark says: "I know where we have to go."

Melisandre, a Red Priestess of the Lord of Light, then intones: "There is only one hell, the one we live in now."

King Joffrey yells at Tyrion: "I said kneel."

And the half-minute long promo ends with a dragon circling over King's Landing.