Metallica bassist Jason Newsted is collaborating on a song with the cryptic Brazilian metal-group, Sepultura, for that band's forthcoming album, which is due out this fall.

According to one Sepultura fan site, Newsted worked on the as-yet-untitled song recently with the band during an impromptu session at the bassist's home in San Francisco.

As we previously reported (see "Sepultura Coughs Up New Vocalist"), the hellfire and rock-strom group recently tapped Derrick Greene to serve as its new gravel-throated singer, filling the position left open by founding member and vocalist Max Cavalera.