Writer Neil Mccormick felt "uncomfortable" naming his memoir Killing Bono until the U2 star urged him to use the quirky title.
The Irish music critic detailed his experiences growing up with the rocker in his memoir, Killing Bono: I Was Bono's Doppelganger.
MCCormick dreamed of being a pop star but failed to achieve any success and had to watch as his school friend went on to become the frontman of one of the biggest rock acts ever.
The book has now been made into a movie called Killing Bono - a title MCCormick was uneasy about but which the singer loved.
MCCormick tells U.K. TV show This Morning, "At a certain point, he was getting hard to know because I was in the Wembley Coach and Horses (pub) and he was in Miami doing duets with Frank Sinatra.
"He was telling me about all these things. I said, 'I don't wanna hear it. The problem with knowing you is you've lived my life.' He said, 'That's because I'm your doppelganger. If you want your life back you'll have to kill me.'
"In there, a little light bulb went off. Really it's a metaphor - it's about slaying your dragon. He was my dragon. He thought it was a great idea for a title, I was a little uncomfortable about it. He told me I should call it Killing Bono. He left a message on my answerphone one day, saying, 'Hey it's Bono, you have to kill me - it's for your own good.'
"He's right, it's a great title but I have to emphasise no Bonos were harmed in the making of this movie."
MCCormick reveals the Beautiful Day hitmaker had only one problem with the movie, adding: "He thinks it's very funny (but) he thinks the actor playing him should be taller... What I really wanted was to cast Danny DeVito as Bono. The guy who plays Bono is more like Bono than Bono is. It was so spooky, I turned around when he walked on set and I thought, 'What's Bono doing here?' Bono said, 'Just as long as he's tall.'"
Affleck was recently confirmed to be NOT directing 'The Batman', despite many rumours that he would be doing so.