Gargantuan fantasy role-playing game Skyrim is the fastest-selling game in Steam's history, Valve has revealed.

"Bethesda's commitment to and understanding of the PC as a gaming platform shows in the great review scores, spectacular launch, and continued high player numbers that Skyrim has received," Valve director of business development Jason Holtman said.

"We are delighted that Bethesda chose to use Steamworks to support Skyrim both at retail and digitally."

According to Bethesda parent company ZeniMax, a whopping 10 million units of Skyrim have been shipped for the PC, PlayStation 3 and Xbox 360 versions.

This, the company said, represents around $650 million in retail sales since launch.

In the US, the PC version outsold all other PC games by a factor of over three to one in the month of release. ZeniMax noted "large retail reorders across all platforms" and "record-breaking digital sales".

ZeniMax boss Robert Altman said: "We are gratified that Skyrim continues to garner high review scores and accolades around the world.

"We are most grateful to our fans for their support and enthusiasm for the game, and their love of the hundreds of hours of gameplay it offers. We continue to strive to deliver the highest quality entertainment experience for everyone.

"2012 will be another huge year for our fans, with the release of the Creation Kit, as well as exciting DLC which will add to the richness of this epic adventure."