The singer-and-political activist - who organised the event alongside rocker Midge Ure on July 13 1985 to raise funds for famine relief in Ethiopia - insists he wasn't bothered whether he looked "a prat" if it failed, but was worried about letting people down.
He told Absolute Radio's Live Aid 25 Documentary: "There were hundreds of thousands, if not millions, depending on this thing working. I didn't really give a toss that it would fall on me, of course I'd look a complete prat to the entire world, but frankly by that stage I was quite used to that.
"I'd woken up a lot at night afraid that this was going to be a disaster, like afraid of small things, like that people weren't going to show up, which in the clear light of day probably couldn't have happened.
"It sounds pious now, but I was absolutely aware of what this was about, and although it would have been a personal cock-up, I think to let down those in whose name all these people were doing it would have been criminally irresponsible."
However, the 'I Don't Like Mondays' songwriter - who helped to raise more than £150 million for charities and non-governmental organisations in Ethiopia - admitted the groundbreaking concert featuring the likes of The Who, The Beatles and Status Quo was a success "in almost every instance".
He explained: "In almost every instance, Live Aid worked. It worked artistically, it worked technically.
In terms of creating a political lobby for change, it was arguably one of the most successful. We were able to change laws which will into the future have a huge long-term effect on Africa. Not a penny, not a single penny went astray, not a single penny went to a government, every single penny as promised went to someone who needed it."
To download the Live Aid 25 podcast, log on to www.absoluteradio.co.uk.