The U2 frontman, who has an older brother called Norman, revealed on BBC Radio 4's Desert Island Discs that he didn't know about his father's other son for decades.

"I do have another brother whom I love and adore that I didn't know I had, or maybe I did," Bono explained. "It's a very close family and I could tell that my father had a deep friendship with this gorgeous woman who is part of the family and then they had a child and this was all kept a secret."

He recalled the conversation he had with his father Bob about his secret son after he found out in 2000, a year before Bob died in 2001.

"I asked him did he love my mother and he said, 'Yes' and I said, 'How could this happen?' He said, 'It can', and that he was trying to put it right, trying to do the right thing. He wasn't apologising, just stating these are the facts," he said, before adding that he's "at peace with it".

The 62-year-old shared that his mother Iris, who died in 1974, did not know her husband had fathered another woman's child.

"Nobody knew," Bono stated. "My father was obviously going through a lot, but partly his head was elsewhere because his heart was elsewhere."