Blizzard have announced that the closed beta for the third World of Warcraft expansion, Cataclysm, has started and invitations to participate in the beta have been sent to players who signed up via their accounts.

"Our focus with Cataclysm has been to build on the knowledge we've gained through the previous expansions to deliver the best, most compelling World of Warcraft content for our players to date," said Mike Morhaime, CEO and cofounder of Blizzard Entertainment. "Gathering focused feedback during the beta test will go a long way in helping us reach that goal when we launch Cataclysm later this year."

Cataclysm is the third expansion for World of Warcraft, where, the face of Azeroth will be forever altered by the return of the corrupted Dragon Aspect Deathwing. Players will explore once-familiar areas of the world that have now been reshaped by the devastation and filled with new adventures.

Two new two new playable races, the Worgen and the Goblins, and a new level cap of 85 are all part of the changes.