Everybody who has known Damon Albarn for any length of time comments on two things: his extraordinary self-confidence and his competitiveness. He is, by all accounts, alpha male in excelsis. His schoolfriend from Stanway Comprehensive in Essex, Graham Coxon – with whom he founded the band that became Blur – remembers how, in the early days, Albarn would drive them, uninvited, to other groups’ gigs and hustle a half-hour slot on the bill. “Damon was absolutely terrier-like, quite unlikable in a way,” he says.

After the band signed to Food Records (later acquired by EMI) in 1989, their go-to guy at the company, Tony Wadsworth, noticed how “Damon was so cocky he found it difficult to go anywhere without getting punched”. Wadsworth was convinced that Albarn would succeed: “He had huge talent and he was relentlessly ambitious,” he says.

Later on, in 1995, there was the Britpop “battle of the bands” episode – a chart contest initiated by Albarn in which, in a blaze of skilfully orchestrated publicity, Blur’s single Country House beat Roll With It by Oasis to the No 1 slot. That joust turned nasty, with Noel Gallagher publicly stating that he hoped Albarn would die from Aids. But many of Albarn’s enduring friendships seem to have had competitive roots too. Jamie Hewlett, the creator of the Tank Girl cartoon strip and, since 2000, Albarn’s partner in their virtual band Gorillaz, says that when they first met in 1990 they “didn’t like each other, and I think that was because we were quite similar, equally confident, a bit arrogant”. It was eight years before the two men really spoke, and in no time at all they became flatmates, bandmates, and soulmates who still live across the road from each other in west London, and sometimes holiday together, now that they’re settled with kids.

This is often the way it works with Damon Albarn, apparently. According to another musical sparring partner, Blur’s bassist, Alex James, “In the Robin Hood stories, Robin likes to have a fight with everyone he meets before he becomes their friend. Damon loves Robin Hood and he loves a tussle.” As time has gone by, and he’s turned 40 and become a father, his fondness for Hood-like tussles has turned into something more mellow and eccentric.

In the converted paint factory near London’s Westway that now serves as his and Hewlett’s studio and HQ, I no sooner hunker down on the back terrace with this lively, stubbly character whose crooked, gold-toothed grin lends him a piratical air, and whose accent is itself a contest between the genteel and the estuarine – “wiv” for “with” being a favourite Damonism – than Albarn is off. As a passenger train rattles past the square, four-storey building, he leaps up and waves energetically in the train’s direction. He keeps this up, at intervals of 10 minutes or so, for the duration of our two-hour interview. He claims he does it any time he happens to be within waving distance, despite the fact that nobody, so far, has waved back. The most he’s ever got by way of response, he says, “was a horn and half an arm once from one of the drivers. Generally, no one’s looking when they come past here, for some reason”. Undeterred, he is determined to keep on waving.

With anybody else, this might seem like a pointless charade. With Albarn, it feels like an authentic expression of that bumptious, competitive personality of his – an outrider of his boyish exuberance, his relentless attention-seeking, his unbridled compulsion to communicate. In particular, it stands as a slightly comedic example of his tireless recent pursuit of goals that look, on paper at least, either unlikely or unachievable, or both.

He has set himself quite a few of these since he began diverting from Blur. The 21st century has found Albarn in a frenzy of career swerves that has established him as an unpredictably protean figure. Not since David Bowie in the 1970s has one pop person covered so much diverse ground. First there was Gorillaz, the wildly popular virtual hip-hop group based around Jamie Hewlett’s Japanese-style cartoon animation, whose two albums have already outsold Blur’s entire catalogue. Then came Albarn’s conversion to African music following a trip to Mali with Oxfam in 2000. This culminated in Albarn lambasting Bob Geldof’s Live 8 for excluding African artists, and setting up Africa Express, an organisation that facilitates intercontinental concert jams like the one that took place in Liverpool in March this year featuring, among others, the Scottish rock band Franz Ferdinand and the Senegalese vocalist Baaba Maal.

It’s not as if Albarn has totally abandoned being a rock star, or forsaken the limelight for the impresario’s role.

For anybody who missed his mockney vocal presence in front of a band, there was, in 2003, Think Tank – a Blur album in name at least, despite the absence of the linchpin guitarist and recovering alcoholic Graham Coxon. Albarn was back out there again in 2006 with The Good, the Bad and the Queen, a concept album about London through the ages that found him in temporary cahoots with the Clash’s old bassist, Paul Simonon, and the legendary Afrobeat drummer Tony Allen.

But all of the above rank as sideshows in comparison to the project that has absorbed most of his attention for the past three years. Monkey: Journey to the West is an extraordinary piece of Chinese musical theatre conceived by the Gorillaz duo in collaboration with the director Chen Shi-Zheng. Based on an ancient folk tale, and acted and sung in Mandarin, with visuals by Hewlett and a score composed by Albarn, mainly using the traditional Chinese five-note, or pentatonic, scale, Monkey bears little resemblance to anything Albarn – or anybody else, for that matter – has done before. (The commission came to him through contacts he made at the Barbican Centre in 2002 while staging a concert of Malian music.) Premiered at the Manchester International Festival in June last year and performed since at a series of opera houses across Europe, Monkey has attracted the best reviews of Albarn’s already pretty-well-reviewed career.

He took some persuading to sign up for his most ambitious project to date, and only finally agreed to it after two reconnaissance trips to China, during which he visited the Dhong people in the south and then stayed in Chengdu near the Tibet border. He says he became entranced by Chinese culture after visiting a temple high in the mountains that was connected to the valley below by a 42-kilometre stone staircase. Albarn then went and stayed with a Chinese composer in Beijing who had a collection of 500 books of folk songs, an experience that inspired his own score for Monkey.

It is not over yet. In November, a revised version of Monkey, shortened and with an interval, “so it works better for a much wider audience”, returns to London for a four-week run in a 2,500-capacity tent next to the O2 centre, or the Millennium Dome as was. The hope is that, along with attracting a less arty crowd, the production might finally make some money for its creators, who are, so far, out of pocket on the enterprise to the tune of about £1.2m. This was the sum Gorillaz had to pay to secure all rights to the performance from the French government, who funded the original production through the Paris-based Châtelet opera company.

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