Heavy rockers Testament have reunited with former bandmember Steve Digiorgio after their current bassist left the line-up.

Greg Christian has exited the metal band and the musicians have confirmed DiGiorgio is rejoining to take his place.

A statement posted on the official Testament website reads, "It is with much respect that we announce our mutual parting with bassist Greg Christian. Metal fretless bass pioneer Steve DiGiorgio will be returning to Testament.

"Steve previously was a member of Testament on (1999 album) The Gathering... as well as (2001 album) First Strike Still Deadly... He will be joining Testament on their upcoming shows in Australia on the Soundwave Festival, Japan and Mexico City. Steve will also be taking part in the new Testament album. We are looking forward to continuing the momentum you, the fans, have made possible."

Christian previously left the group in 1996 but rejoined in 2004.