The guitarist of the now defunct BULLET IN THE HEAD rockers almost ditched the idea of working with De La Rocha, but he was blown away when he gave De La Rocha a second chance.
Morello says, "Much to my surprise Zack began rapping at the first jam session in a bedroom in the (San Fernando) Valley.
"It didn't sound great and I left thinking I'd never see those guys again.
"A few weeks later, though, I decided to try again and Zack was phenomenal.
"He freestyled for an hour-and-a-half that day, full of fire, indignation and raw emotion.
"I remember thinking, 'This guy is frigging incredible.'"