One of the world’s richest men, Microsoft co-founder Bill Gates, and his friend Bono didn’t always have such a chummy relationship.  The two, who work closely together on the AIDS crisis in Africa, share the December 3 cover of Forbes magazine to talk about their work and how they came together.

Bono sought a meeting with Gates years ago to talk about how they could combine their talents, but Gates wasn’t interested. Bono reached out to a mutual friend, Microsoft co-founder Paul Allen, but the response wasn’t initially positive.

“I had no idea, of course, that [Allen had] been asking Bill, but Bill was actually like, ‘No, I don’t want to meet him! It’s Sonny Bono, or whatever,’” Bono told Forbes during a joint interview with Gates, who with his wife Melinda leads the world’s biggest philanthropy, the Bill and Melinda Gates Foundation.

Gates also remembers not wanting to meet the Irish rock star, who has worked tirelessly for years on the myriad issues affecting Africa.

“Paul said to me several times, ‘You know, Bono is really serious about poverty and the stuff you’re working on; you should talk to him.’ And I have to admit, I did not make it a priority,” Gates recollected.

“And then there was a Davos [meeting] that was in New York after 9/11, so Bono, Bill Clinton and I met, and I was kind of amazed that he actually knew what he was talking about and had a real commitment to making things happen. It was phenomenal. Ever since then we’ve been big partners in crime.”

Bono was asked about a possible second act in life – as if he doesn’t have his hands full with U2 and his work with activist groups like RED and ONE.

“I haven’t left my day job yet, though there’s always this possibility when U2 puts out an album that no one will be there to buy it. And according to my band, if I keep doing these type of events, that’s going to be closer than we thought,” Bono said.

“I have a tricky one, you know, because I have to balance being an artist, which is my gift, and being this salesperson. In U2, I sell melodies, I sell songs. Here I try to sell ideas, but I have to believe in them, and then I’m a pretty good salesman.”

Speaking of a new U2 album, Billboard magazine reported last week that it’s looking like April will be the release month. It was also reported that the official announcement will be made during a Super Bowl commercial.