According to a posting on Metallica’s official web site, their much-anticipated appearance on “The Simpsons” will air as the program’s season premiere on September 10, 2006 on the Fox network. The four members of Metallica recorded their voices for the program last September.
Metallica’s James Hetfield and Kirk Hammett — along with members of Arch Enemy and Nevermore — have previously lent their voices to the cartoon series “Death Clock Metalocalypse”. This is their first appearance on The Simpsons.
SOURCE: RoadRunner