This is Jack Black From Tenacious D, The Pick of Destiny

In Venice Beach, there was a man named Kage
When he was buskin he was all the rage.
He met Jables and he taught him well,
all the techniques that were developed in hell.
Cock pushups and the power slide,
gig simulation now theres nowhere to hide.
They formed a band they named Tenacious D,
and then they got the Pick of Destiny.

Tenacious D - The Pick of Destiny