The Lannisters and Starks are well-represented, but there are also glimpses of new castmembers Paul Kaye, Thomas Brodie Sangster and Ellie Kendrick.
Game of Thrones story editor Bryan Cogman revealed earlier this month that several main characters will be killed off before the season ends.
"We get more and more amazing cast members every year and we kill a few too to make room, and that tradition is going to continue in season three," Cogman explained.
"More of less we're covering seasons three and four with the events of A Storm of Swords but from now on we're not looking at a book per season, there's going to be a lot more blending of elements of all the books as needed."
Emilia Clarke - who plays the Khaleesi - also recently declared that season three is her favourite thus far, saying: "I've never in my life been more excited to see a season as season three.
"It's gonna be good!"
HBO premieres Game of Thrones season three on March 31 on HBO in the US and it will debut a day later on Sky Atlantic in the UK.
> Nikolaj Coster-Waldau on Game of Thrones: 'I had doubts
Watch a teaser trailer below: