Blizzard Entertainment has announced plans for World of Warcraft (WoW): Mists of Pandaria (trailer posted below), the fourth expansion for the massively multiplayer online role-playing game (MMORPG). The game’s third expansion World of Warcraft: Cataclysm sold over 3.3 million copies in the first 24 hours following its release and more than 4.7 million copies in its first month.

World of Warcraft: Mists of Pandaria lifts the fog of mystery surrounding a long-lost continent that has been newly rediscovered, following the events of the current expansion pack. The new expansion reintroduces the elusive pandaren, originally seen in Blizzard's real-time strategy game Warcraft III, as a playable race, and adds a brand-new player class: the martial-arts-focused Monk.

While exploring the mysteries of an exotic new land and advancing to the new level cap of 90, players will experience a range of new content and game features, including new quests and dungeons, group scenarios as well as "challenge" modes and pet battles.

"Players have been asking to see the pandaren in World of Warcraft since the game's launch, and we're excited to finally be able to give them a proper re-introduction to Azeroth," said Mike Morhaime, CEO and cofounder of Blizzard Entertainment. "In addition to the new playable race and class, Mists of Pandaria contains a huge amount of new content, and we're looking forward to sharing more information about all of it at BlizzCon and beyond."

New features that will be available in the game's fourth expansion include:

• New playable race - Pandaren: Adventure through Azeroth as World of Warcraft's first neutral race and decide whether to side with the Alliance or the Horde.
• New playable class - Monk: Unlock the secrets of pandaren martial arts and do battle as a damage dealer, healer or tank.
• Level cap increased to 90: Learn potent new spells and abilities while exploring uncharted zones and taking on challenging new content.
• New zones: Explore the lush Jade Forest, treacherous Kun-Lai Summit, as well as other exotic areas of Pandaria designed for high-level characters and uncover the mystery of the Wandering Isle.
• Scenarios: Join up with some friends to achieve a common goal, the likes of mounting a defense against invading monsters, in a flexible new type of PvE (player vs environment) challenge.
• Dungeon "Challenge" modes: Master the ultimate five-player time trial to earn prestige rewards in a new dungeon mode that will put your resolve and coordination to the test.
• Pet battles: Challenge other players' companion pets with your own collection in a new tactical mini-game and find out who's king or queen of the pint-sized battlefield.
• New talent system: Customise your character to suit your play style with the newly overhauled and improved talent system.

In related news Blizzard Entertainment announced last month that the highly anticipated Diablo III will definitely not see a Christmas release this year, since the launch window has moved to early 2012.