The trailer shows a mixture of cinematics and gameplay sequences from the PC strategy game, which is based on the best-selling A Song of Ice and Fire series by George RR Martin.
Set on the continent of Westeros, it sees a Targaryen King in battle with various Houses in a claim to the Iron Throne.
A Game of Thrones: Genesis will be available on PC from September 30 worldwide.
> Game of Thrones star Peter Dinklage 'not expecting Emmy win'
> Game of Thrones in for long run, says HBO
Watch the official trailer for A Game of Thrones: Genesis below: