Ozzy Osbourne says he struggles to believe Black Sabbath's success story.

The 64-year-old musician has been blown away by the response to the heavy metal group's reunion in 2012 and their new album this year '13' - the first studio LP to feature Ozzy on vocals since 1978's 'Never Say Die!' - which topped the album charts in eight countries.

Ozzy - who is joined in the band by guitarist Tony Iommi and bassist Geezer Butler - admits he thought the group probably had just a few years ahead of them when they formed in 1968 and is astounded that 45 years on people are still so passionate about their music.

Speaking at the Classic Rock Roll of Honour Awards at The Roundhouse in London on Thursday night (14.11.13), Ozzy said: ''It's embarrassing really; I remember after we'd done one of our first gig, I thought, 'This'll be good for a couple of years.' Here we are, 45 years down the road and we've got a number one album. I had no idea it would end up doing that.''

Ozzy - who was joined at the event by Geezer and Tony to collect three prizes including the coveted Living Legend Award - insists the group owe everything to their fans for their unwavering support and loyalty.

He added: ''It's only because of the fans that we've still got a career, they keep supporting us - 45 years we've been around. It's remarkable. It's fantastic that people are still interested after all this time. It's been a great story to come back and we've done fantastic.''