Blizzard have announced that the latest expansion for its ever popular MMORPG World of Warcraft has topped 4.7 million sold copies, setting a new record for monthly PC-game sales.

The expansion had already set the record for the fastest-selling PC game of all time with day one sales of 3.3 million, beating the previous record which was held by the second WoW expansion, Wrath of the Lich King.

"We created thousands of new quests, introduced new lands to explore and extensively revamped the game world for World of Warcraft: Cataclysm, making it our biggest and most ambitious expansion yet," said Mike Morhaime, CEO and cofounder of Blizzard Entertainment. "We've been floored by the community's response so far, and we'd like to thank them for their continued passion and support for World of Warcraft, and for helping Cataclysm reach this incredible milestone."