The first trailer for Alex Gibney's upcoming HBO documentary Going Clear: Scientology and the Prison of Belief has been unveiled, have a look here.

The Oscar-winning documentarian takes a look at the origins of Scientology, its rise to prominence and its current practices.

The documentary, which is based on author Lawrence Wright's book, premiered at the Sundance Film Festival last month to widespread acclaim.

It will debut on HBO on March 29.