The 57-year-old Irish musician and political activist said campaigners marching in London against Thursday's political gathering have a powerful voice.
He told the Sunday Telegraph: "I think that they are a force for good. A global economy needs to include the poor.
"Sometimes protest is the best way of getting the point across. I hope that it achieves results, but I hope, too, that it will be peaceful."
The former member of The Boomtown Rats worked with Midge Ure to produce the 1984 Band Aid single 'Do They Know It's Christmas?', and was also behind Live Aid the following year and Live 8 in 2005.