Electronic Arts responded immediately upon Blizzard’s “Bard Hero” announcement, that it filed a patent infringement lawsuit against Blizzard Entertainment, related to the recently announced “Bard Hero” class addition to be featured in the highly anticipated “World of Warcraft: Wrath of the Lich King” expansion.

The lawsuit, filed in Federal District Court in California, relates to a similar patent claim involved in another suit between Gibson and filed earlier against various retailers and EA over the guitar game interface used by Guitar Hero.

The “World of Warcraft” series combined has sold more than 3.64 million units in North America and raked in more than $1.2 billion in 2007 alone for their parent company, Vivendi SA.

Electronic Arts said the planned game class, in which players use a large guitar-shaped axe controller in time with notes on a computer screen to unleash killer riffs with the power of rock to defeat virtual monsters, violate numerous 2005 Guitar Hero patents.

Harmonix developed the first “Guitar Hero” game and was later bought by MTV. Electronic Arts and another company, Activision Inc., as well as several retailers, either develop, distribute or sell one or several of the games in the “Guitar Hero” series.

A representative for Blizzard Entertainment could not be immediately reached for comment on the pending litigation.