Sir Elton John has called last month's Live 8 concert "an anti-climax" that lacked many highlights.
Sir Elton said he was pleased to be part of Live 8
Speaking to the Telegraph newspaper, Sir Elton said the concert in London's Hyde Park lacked "a sense of occasion".
"I was very pleased to be a part of it, but I didn't think it was anywhere near as good as the first one. How could it be?" he said.
Sir Elton sang a duet at Live 8 with Babyshambles singer Pete Doherty, which failed to impress critics.
Doherty 'a mess'
Sir Elton said they had rehearsed their rendition of Children of the Revolution to "tip-top" perfection.
But he said on the day he thought Doherty was "really nervous", which affected the performance.
Sir Elton said Doherty was "a mess" and added: "I don't think the people around him set a good example, which is a shame."
Speaking about Live 8, Sir Elton said: "The thought behind it was fantastic but Hyde Park is a charisma-free zone.
"There was no sense of occasion and from a musical point, I didn't think there were too many highlights."
Pete Doherty performed a duet with Sir Elton in London's Live 8 concert
London's Live 8 concert was one of a series of global gigs organised by Bob Geldof to highlight poverty in Africa and third world debt.
Among those who performed were Robbie Williams, Coldplay, Sir Paul McCartney and Madonna.
Sir Elton also admitted that he had a tendency to upset people with his outspoken views, including Madonna and George Michael.
He said he had made amends with George Michael but that Madonna had not forgiven him for his public claim that she mimed on stage in 2004.
"I did send her two Christmas cards and they both came back," Sir Elton said.