Modest Mouse should have had it all made by the end of 2004. Their fourth album, Good News for People Who Love Bad News, had become their most successful yet, reaching No 18 in the US charts and spawning a big hit, Float On. That song was a gloriously uplifting pop single, built around a guitar pattern conceived by guitarist Dann Gallucci in the style of the former Smiths guitar player Johnny Marr.
There was a problem building on that success, though. Gallucci had left the band in August. Who could replace him when it came time to record the follow-up? Who could take Float On a step further? Then Isaac Brock, the band's frontman, had an idea. "I knew it was a demented notion," says Brock of deciding to ask Marr himself to work with Modest Mouse. "But I just figured that just because he'd filled a massive part of his life building the Smiths legacy didn't mean he was busy at that precise minute."
Brock tracked down Marr, 11 years his senior, and despite the logistics (Modest Mouse are based in Oregon, while Marr comes from Greater Manchester) Marr was intrigued. He knew and liked Modest Mouse, and could see the attractions of working with them. "I thought, 'This is insane but interesting,'" he says. "We don't know each other but we're going to have fun trying." The upshot was that Marr would travel to the US and work on the next Modest Mouse album.
Things took off from there. The night before we meet, Marr has played his first UK gig as a fully fledged member - guitarist and songwriter - of the band Brock describes as "a bunch of oddballs". And the chemistry between the pair is obvious. "We get on so well it's pretty sickening, actually," says Marr. "I like you even more," grins Brock.
The obvious connection is musical. When Brock called, Marr was not only at a loose end, but developing a new guitar sound - "fat, clean, attitudey but not rocky". He'd been working on it for a few weeks when he teamed up with Modest Mouse, and had to find a way to make it work with a band who had their own well-developed sound. "I never really realised how Isaac played," says Marr. "Standing in front of his amps he has a very expressive and big, punchy sound. I thought, 'I can either be textural and melt into the background, or I can try and really get some choreography going with him.' That was my only agenda."
On Dashboard, the first single from the forthcoming album We Were Dead Before the Ship Even Sank, Marr's chiming, mellifluous funk riff counterbalances Brock's unhinged vocal: it's something like a collision between Pere Ubu and the Smiths. The song was written the first night they met. "I remember waking up the next morning jet-lagged and thinking, 'Did we really write a great little pop tune last night?'" says Marr.
Brock and Marr managed to begin working without too many preconceptions about each other. The former says he gave up reading about his heroes in his teens after finding out that the lyrics of the Pixies' Debaser weren't as exciting as he thought (he now refuses to explain his own lyrics). Similarly, Marr says he "didn't Google" Brock. Which means he hasn't heard about Brock's bizarre background. When the subject comes up, and Marr discovers the truth, he asks: "Where's my coat?" "Wait, Johnny, don't go," pleads Brock, grinning. "I was gonna tell ya!"
Brock was raised within the Grace gospel church - which was affiliated to David Koresh's doomed Waco Branch Davidians. He says his family were young at the time, and at least they got out of it. Nevertheless, when he was six he was expected to speak in tongues for the benefit of the church. "I didn't feel the spirit of the fucking Lord rushing through me," he says. "I definitely felt awkward. I thought. 'What's the best way to make this stop?' So I ripped off some words from Mary Poppins and said them fast, and the deacons are going, 'Yeah, all right!'" These days, his mother is a Wiccan. "She meets women, they cast spells," he says offhandedly.
If anything, it gets stranger. After forming Modest Mouse in 1993, Brock had to participate in clinical trials to raise enough money to keep the group going. And he was once charged with attempted murder after driving under the influence of laughing gas. As Brock explains it, a passenger handed him the gas, and he crashed the car, causing her to dislocate her thumb. But under Oregon law, any injury caused by driving under the influence is considered to be attempted murder (though his lawyer didn't tell him that at time).
Shortly afterwards, he was coming back from a trip to Niagara Falls in Canada when he was stopped at the US border. "The border guy asked, 'Did you purchase anything?' I said 'Fudge,'" he sighs, "and the second I said it, I knew it sounded like 'Fuck you, border guy!'" On checking, the official discovered Brock was a fugitive charged with attempted murder. The singer spent 10 days in jail, before escaping with probation. "Not a nice place," he says.
"I know about clink-clink," replies Marr. It turns out he, too, has spent time in jail. At 16, he says, he was locked up for three days. He had, apparently, been found in possession of some stolen Lowry prints.
In fact, perhaps their backgrounds aren't so different. Marr says the Smiths were also "misfits and wild cards". Modest Mouse took their name from Virginia Woolf's description of ordinary people, echoing the Smiths' notion of an everyday, anonymous but memorable name. Both bands have had members leave in dramatic circumstances (Smiths bassist Andy Rourke owing to heroin; Mouse drummer Jeremiah Green - who's now rejoined the group - following a "meltdown" induced by antidepressants).
There's a lifestyle gulf, though: Marr nurses an orange juice; Brock favours lager and cigarettes, though he says he is forever trying to quit. Brock once addressed his substance abuse in a song drily titled The Good Times Are Killing Me.
"It's to do with age," says Marr. "If we'd have talked 10 years ago, I'd have been on the fags and I'd have been too hungover to start on the Grolsch." However, he points out that while they are "very different people", there are other things in common: both, for example, know about the enormous baggage that accompanies sudden success (while Marr's presence in Modest Mouse might be a big deal in the UK, the band are definitely the bigger name in the US).
Brock, however, seems less concerned about that than the baggage that comes with recruiting Johnny Marr. One interviewer asked him whether Modest Mouse recruiting Marr is preventing a Smiths reunion. "There's a negativity in some of the enquiries that's fucking shitty." He turns to his partner. "I don't know how you tolerate that, man." For his part, Marr says he's rarely asked about the Smiths any more, except by journalists. "There's an interest in keeping a certain soap opera going and it's no secret that there was a lot of antagonism amongst the band members," Marr says. "But it's 20 years ago. I don't wanna carry that baggage any more. People should get over it."
Last year, Marr played a couple of Smiths songs with his former bandmate Rourke at the Manchester v Cancer charity gig and revelled in the "positivity" of 15,000 fans holding up their mobile phones to photograph them, but otherwise he has no interest in looking back: playing in Modest Mouse is reaffirming his status as a "maverick guitar player". The obvious question is how long it will last, but Marr says that after agreeing to join the band for one album, he's already contemplating the next. But he describes the music of Modest Mouse, like that of the Smiths, as "joyous".
The previous night, on stage in London, he had felt the same energy he had with Morrissey singing, more than 20 years earlier. "The feeling in the audience was similar," he says. "That sense of communal excitement, more than just guys punching the air." And, from the back of the hall, he had looked like the Marr of days past: thinner than for years, immaculate of hair, and bobbing about the stage as if this were the biggest crowd he had ever played for.
He thinks back to one of his first sessions with Modest Mouse. "On the fourth or fifth day, when all six of us were playing, we saw some homeless people hanging outside Isaac's house," he says. "It occurred to me that I had no idea where this music was coming from but I could see them dancing in the dark. The experience was like a short circuit to my feet."
He pauses for a moment, and then smiles at his friend. "Sometimes you've just got to follow your instincts."
· Dashboard is released by Epic on March 26. We Were Dead Before the Ship Even Sank follows on April 2
