This revelation came after I had quoted from an article in last month's Mojo magazine, in which an unnamed source hinted darkly at the "drugs and sex" in the REM camp, about which the world never hears. The thrust of this "incredibly silly piece", in Mills's words, was that REM were on the verge of splitting up. In fact, the closest they got to that verge was last year, when their drummer, Bill Berry, was struck by a near-fatal double aneurysm, in the middle of the band's world tour. "At that point it was pretty much up to Bill, and whether he felt he could continue," says Mills. "If one of us were to leave the band, we'd either break up or at the very least change the name, because that would in fact be the end of REM."
Don't hold your breath. The speed of Berry's recovery was matched only by the speed at which REM came back with a new album, New Adventures in Hi-Fi. What's more, they're so happy with it that they have signed a deal with Warner Records for a further five albums. When the king's ransom of royalties rolls in, this contract could net Mike Mills, as one quarter of REM, $20m. Does he think that entertainment stars get paid stupid amounts of money? "Sure. But nobody's gonna send the cheque back. It's about security, it's about being able to take care of your family, it's about being able to do the job you do as long as you want to do it, and if money provides that then I'll take it."
Like most multi-millionaires, he doesn't look like one. He sits beside a bedroom table in Dublin's Clarence Hotel - an establishment owned by U2. He wears a pale yellow jogging shirt, he has round glasses and a round face, sunburnt from too much golfing. He speaks quickly and fluently, in a Southern accent, fitting so many words into one breath that it's no wonder he has the job of holding the long notes in REM. His favourite words are "cool" and "rock'n'roll", but he can casually reel off a sentence that most people in his business couldn't spell. Would he start his own record label? "The thing about me, as a musician, is that once you introduce the concept of the bottom line, it is by nature incompatible with the artistic impulse, and the reconciliation of those two things is the dynamic that fuels the music business." And he's just the bass player, mind.
REM are a phenomenon. It's been 16 years since Mills, Berry, Michael Stipe and Peter Buck got drunk in a deconsecrated church in Athens, Georgia, and chalked possible names on the concrete wall, rejecting Cans of Piss and Negro Eyes in favour of REM. Since then, they have travelled into uncharted rock territory. With the possible exception of U2, it's hard to think of another band that have lasted as long while keeping their original line-up, releasing records regularly - to at least as much critical acclaim and commercial reward as ever - and doing it all on their own terms. As the TV programme says, how do they do that?
Maybe REM should write a book for rock bands on How to Keep Your Marriage Alive. Chapter One would be "Know the Pitfalls". "By the time we started the band we already knew a lot about rock'n'roll. Peter read every magazine that had been written, and Bill worked for a booking agency, so we had a pretty good idea of what not to do. Like, Peter's idea to split the songwriting credit four ways, I was against that. I said, if I write the song, I want the credit. He said, yeah, but countless bands have broken up because the songwriters get more money than anybody else, so it's better for the band if we do it this way. And he's been proven right over and over again."
Secondly, know your limits: no skidding off the rock'n'roll path and down the slippery slope into oratorios and rock operas. "I don't have any illusions about being to write any sort of opera. I know enough about classical music to know how difficult it is. You have to have a huge understanding of the nature of music which is in a way almost antithetical to the nature of rock'n'roll. Rock'n'roll comes a little more from the heart, and in classical music you have to use your head a lot - and I don't wanna work that hard!"
What about dance music, which is, in Britain at least, perceived as the cutting edge, while rock music is seen as retrogressive? "Well, I don't dance, so it has absolutely no interest to me whatsoever. I think that by and large it's pretty boring, it's so beat-driven. I'm a melody guy. If there's no melody, I don't have much interest in it. And what's cutting- edge today could easily be tomorrow's crap. Will dance music matter next year? I doubt it. I really doubt it."
Thirdly, don't get too famous too soon. REM had been going for more than eight years before they hit mainstream stardom. "Whatever pressures there are to fame and success came upon us gradually. I would not have wanted to go through what even the Go-Gos had to go through, much less Pearl Jam or Nirvana. It's a lot to ask of a person with no practice or training."
Speaking of Nirvana, Kurt Cobain opined that REM had dealt with their success like saints. Surprisingly, Mills chuckles at this. "I think saints is a bit of an inaccurate word, but he was just being emotive. I think we've dealt with our success like intelligent people. I'd probably leave it at that."
'New Adventures in Hi-Fi' is out now. A video, 'Roadmovie', recorded live in Atlanta in November 1995, is released tomorrow. REM's next single, 'Bittersweet Me', is out on 21 October.