Billionaire rapper Jay-Z's new book Decoded hits shelves in Australia, coinciding with his performance at U2's concert in Melbourne today. Random House Australia says the book provides "unparalleled" insight to the relationship between Beyonce's husband and the supergroup frontman Bono.

The two were first introduced in a cigar room in London. Jay-Z and U2's Bono collaborated for their benefit song "Stranded (Haiti Mon Amour)" as part of the "Hope for Haiti Now." Now they are teaming up again as Jay-Z supports U2 in the Australian leg of their '360 Degrees' world tour.

In Decoded, JAY-Z talks about his first encounter with Bono and the friendship they developed.

"Bono's got such a pure soul and positive energy - his eyes almost literally light up and dance when he's excited," writes the richest rapper in American entertainment industry.

In his highly personal narrative, JAY-Z discloses what it was like meeting Bono for the first time and what he said to make Bono go back into the studio to rework an already finished album.

"One night I ran into him [Bono] and he told me he'd read an interview I'd done somewhere. The writer had asked me about the U2 record that was about to be released and I said something about the kind of pressure a group like that must be under just to meet their own standard," Jay-Z tells the readers.

"Bono told me that my quote had really gotten to him. In fact, he said it got him a little anxious. He decided to go back to the studio even though the album was already done and keep reworking it till he thought it was as good as it could be."

Jay-Z had performed at U2's concert in Auckland, New Zealand. He then flew in to Melbourne over the weekend with his wife Beyonce Knowles and rapper Kanye West, with whom he is working on a collaborative project. The supergroup U2 will play at Etihad Stadium in Melbourne today.