Black Sabbath's keyboardist Geoff Nicholls died on Saturday (28 January) following a lengthy battle with lung cancer. He was 68 years old.

The news of Nicholls' death – who was with the rock band until 2004 – was confirmed by the heavy metal band's guitarist Tommy Iommi, who called the musician a "true friend" on Facebook.

"I'm so saddened to hear the loss of one of my dearest and closest friends Geoff Nicholls. He's been suffering for a while now with lung cancer and he lost his battle this morning," Iommi wrote.

"Geoff and I have always been very close and he has been a real true friend to me and supported me all the way for nearly 40 years. I will miss him dearly and he will live in my heart until we meet again. Rest in peace my dear friend, Tony," he added.

Nicholls' former band mate Ozzy Osbourne also paid respects to the legendary keyboardist on Twitter.

"Geoff Nicholls was a great friend of mine for a long time. He will be greatly missed. I'm very saddened at the news," he wrote.

Bassist Geezer Butler wrote on Facebook, "Very sad to hear of old friend and Sabbath keyboard player Geoff Nicholls passing. RIP Geoff [sic]."

Iommi had recruited Nicholls at Black Sabbath in 1979 after Ozzy was fired from the band. Before Nicholls joined Black Sabbath, he was with the Quartz for five years.

He first appeared on the band's 1980 album titled Heaven And Hell. In 1985, Geoff became an official member of the band but left the group after Ozzy's return in 1996. He played for the band occasionally until 2004.