Seen Game of Thrones? Then watch this NOW

If you watched last night's episode of Game of Thrones and thought, "How the hell did they do that?", your question has been answered.

A new documentary posted on YouTube reveals many of the tricks the show's creators used to pull off some of the key scenes of the hard-hitting episode, called Battle of the Bastards.

The 10-minute doco reveals how the grisly Battle for Winterfell was filmed, and reveals those impressive shots featuring Jon Snow on the battlefield were all done without CGI.

It also explains how Snow's Kit Harington spent an entire day pummelling Ramsay Bolton so they could capture the climactic scene from every angle.

And it reveals how they managed to get Wun Wun looking so great on the battlefield.

Seriously, if you love Game of Thrones you need to see this.