The rocker stepped into MACmillan Cancer Support's 'Not Alone' Isolation Box in a bid to highlight the plight of lonely cancer patients in the U.K.

The box allows passers by to see in but leaves the person inside blind to the outside world, evoking feelings of loneliness and isolation some cancer patients experience after their diagnosis.

Iommi was diagnosed with lymphoma in early 2012 and admits he was "in a bubble for a while".

He tells the BBC, "I was absolutely devastated. They're (doctors) talking to me, saying, 'You've got stage three', and it's going in my head and I just felt somewhere else. And it was only later when I really broke down. I thought, 'That's it, it's the end'... but it's not. There are people who can help."

Iommi completed his treatment a year ago (14) but doctors have told him his cancer will more than likely come back. He says, "It could be any time."