US actor Jack Black lives: Tenacious D

Tenacious D has revealed tweets claiming actor and musician Jack Black had died were a "sick prank" by someone who hacked the band's Twitter account.

Jack Black Source: AAP

Jack Black is alive and well despite news of his death on his band's official Twitter account.

A hacker has been blamed for posting a message on Tenacious D's Twitter page that the American actor had died at the age of 46.

The band has called the hacking a "sick `prank'".

Fans rejoiced at the news that the School of Rock actor will "keep on rocking".

"You can't kill the metal, the metal will live on," Chrissie Beddows tweeted.

"So happy to hear Jack is alive and well. What is wrong with people worst `prank' ever," another fan posted.

Black and Kyle Gass formed Tenacious D in 1994.