The cast and crew of HBO's fantasy blockbuster have been enduring cyclonic winds and subzero temperatures for weeks to bring you your latest Game of Thrones fix.

Stars including Kit Harington, who plays back-from-the-dead protagonist Jon Snow, have been forced to endure -25 degree temperatures and 100 mph winds while filming the show's much-anticipated seventh season in Iceland.

HBO pushed back filming in order to catch the worst of Iceland's wintry weather.

The mercury in Reykjavik, the country's capital, regularly plunges below zero degrees in winter. The more remote parts of the Nordic island are even colder: Perfect for a show built around the famous tagline "Winter is coming".

But the eerily beautiful backdrop of Iceland comes at a price. A source told Page Six actors have been battling freezing temperatures and just a few hours of daylight a day.

"Super jeeps are needed to bring in equipment, and much is then transported by hand," the source said.

"The actors are made up and dressed in hotels and driven to location 90 percent ready to shoot. Shelter is provided by 'Russian tents' that are anchored down, and able to be heated, and [can] withstand 100 mph winds."

The filming equipment and actor's extremities aren't the only things to be affected by the cold, however. It turns out the Arctic wind has also made capturing dialogue especially tricky.

"High winds caused words to be 'whipped away' — shouting became the norm," the source said.

"And despite the cold, there was an issue with a lack of snow in the lowland locations."

HBO has not locked in a start date for season seven of Game of Thrones. However, it is expected to be begin screening in Australia around the middle of the year.