Damon Albarn’s new gold front tooth glints in the midday sun. He seems more relaxed and at ease with himself than in our past encounters – which is impressive, given that we find him in the midst of rehearsing an opera about a monkey, to be performed, in Mandarin, at the start of the Manchester International Festival in eight weeks’ time. Pop people and opera have often made unhappy bedfellows, but if one were setting out to design a set of circumstances from which something horrible could arise, it would be hard to trump this, which makes the heady mix of excitement and trepidation around Monkey: Journey to the West deeply understandable. Asked whether there have been times when he has thought “My God, what have I done?”, Albarn causes his boyish features to open out into a smile.

“Well...” he offers eventually, “I think I’ll probably be feeling that right up until the end of the first show. Then I might be feeling it really badly right after that.” Whatever happens, Manchester looks an interesting place to be come June 28.

On the strength of his recent track record, Albarn is entitled to feel that if anyone can pull off something as ambitious as Monkey: Journey to the West, he can. He also knows that its success or failure won’t rest solely on his score, or on the costumes and set being designed by his partner in Gorillaz, the former comic-book artist Jamie Hewlett. The production had its genesis in Paris, when Jean-Luc Choplin of the Théâtre du Châtelet asked the Chinese opera director Chen Shi-Zheng to come up with something he would like to direct. Chen suggested the Chinese story of the monkey king, a folk tale dating from 1592. He knew that the libretto would be drawn from the original text, but that left the question of who would score and design the piece – until Alex Poots, director of this year’s inaugural Manchester festival, recommended Albarn and Hewlett, having worked with the former on Mali Music, a remarkably satisfying collaboration between the Blur singer and Malian musicians.

Albarn and Hewlett, like many thirty- and fortysomething Britons, were familiar with the legend of the monkey king thanks to the eccentric children’s television series that the BBC imported from Japan in the late 1970s. All the same, they were cautious at first, so Chen invited them to China for three weeks, taking them deep into the rural heart of the country, where they ate toads, climbed mountains and got a feel for the music, not to mention for Chen himself. At the end of it, they were ready to commit: all the same, Hewlett describes being stricken with panic for months when he settled down to draw the characters. Albarn, he says, was always “much cooler about it”, visiting China again and taking time to understand the alien conventions of the music, paying particular attention to folk forms. A venerable local musician told him not to worry about being “correct”, but rather to allow himself to operate as a conduit, advice that the Briton seized upon to avoid pastiche – because, as he notes darkly, “You really don’t want to be pastiching Chinese music”.

In many ways, the most astonishing aspect of the Monkey story is Chen himself. Sipping red wine in a cafe across the street from the Théâtre du Châtelet, he is quietly spoken to the point of shyness. With a degree of prompting, he explains that he was born in 1963, during the Cultural Revolution. His father, an intellectual, was removed to the countryside for “reeducation” and kept from his children for 14 years. Worse, when he was four, his Catholic mother, a teacher, was shot and killed while attending a parade, leaving her son and daughter to fend for themselves on the street. His mother’s murder, he says, is his earliest memory.

Salvation of sorts came through a company of actors and musicians who performed traditional operatic rites at funerals. Fascinated by “this beautiful music that could help to transport people through their misery”, Chen hung around until they took him in and taught him to act and sing. Success in his own country was followed by escape to New York in 1987, by which time he knew that his future lay in directing. With an impressive CV in both opera and theatre, he has just directedhis first feature film, Dark Matter, starring Meryl Streep.

The monkey legend is effectively a Buddhist odyssey, in which the impetuous monkey king rebels against heaven and the natural order with the aim of establishing himself as Buddha’s peer. Naturally, Buddha is having none of this, and imprisons the monkey for 500 years before releasing him to accompany an ethereal monk, Tripitaka, and three friends on a quest to the West (in this case, India) in search of a set of holy scriptures. The fable’s tone is bawdy and playful, but its intent is serious, and every Chinese child is familiar with it. For Chen, the secret of the monkey king’s popularity in Asia can be seen in both a political and a spiritual context, with the protagonist’s childlike impulsiveness gradually being mediated by wisdom. He hopes it might spark interest in Chinese culture among Europeans.

“When I was there,” he says, “I did Shakespeare, Chekhov, Molière – every theatre company in China will try to do a Shakespeare play in Chinese at some time. But no theatre company in the West would ever try to do a Chinese play. Maybe this can be the start of something.”

Hewlett has fond memories of the television series Monkey, but it was the first trip to China that persuaded him to get involved. Cradling a coffee in his artfully cluttered Shepherd’s Bush studio, he rejoices in describing the alien, sculpted beauty of the landscapes, and watching old women trudge up and down mountains, baskets of rocks on their backs, fags dangling from lips. Everywhere, there were new sights, smells, tastes. Street vendors roasted dogs and served freshly skinned toads. “China,” he concludes, “is amazing, but not for the fainthearted.”

After he’d signed up, there was a six-month hiatus, at the end of which, he was tormented by nerves and the thought: “Oh my God, we’re doing an opera – where do we start?” To begin with, he tried to adapt his style to the specific needs of the production, and Chen rejected “hundreds and hundreds” of drawings. Finally, the director said: “Just do what you do.” The work flowed, coalescing into 65 characters. “It has taught me to draw again, which is nice,” Hewlett enthuses, while admitting that he fears the costumes might all come out looking like the Honey Monster.

In contrast to Hewlett, Albarn bided his time, waiting until his second Chinese sojourn to begin writing, since when, in his partner’s words, “He hasn’t stopped”. He prowls the rehearsal space with the practised slouch of the composer, nodding and cocking his head to one side as he offers instructions to 15 (Chinese and European) musicians and eight singers – numbers that will ultimately double. The remarkable thing is that, although the songs do sound like they belong in an opera score, with their skewed, Brecht-ian quality, they remain identifi-ably his. He reminds me that he did music A-level, reads and writes music, and plays the piano well; in a way, all this is a return to roots for him, which he is revelling in.

“Actually, it feels like the beginning of a new chapter in my life, because I think it’s difficult to stay in both camps once you’ve entered the world of themes and development, and I’m not sure how I’m going to do it.” He stops and laughs. “In fact, I might have completely f***ed myself here.”

I’m not the only one to have noticed that Albarn is less prickly these days, and wonder whether this is a consequence of greater creative fulfilment. When the guitarist Graham Coxon, his old schoolmate, left Blur in 2002, it was widely regarded as a setback for Albarn, yet the past five years have seen him produce his best work, from the reinvention of Blur to Gorillaz and his ecstatically received new band, the Good, the Bad & the Queen; from Mali Music to co-composition with Michael Nyman, and now Monkey. It’s hard not to be impressed.

“Yeah, I’ve just been dedicated 100%. I have no interest in the affectations of stardom any more. And I use the word ‘affectations’ because being well known is one thing, but the rest is totally surplus. Of course, being able to have the freedom to work because of your popularity is a privileged position to be in, but everything else is a distraction.”

He stays for a while, chatting amiably about China and music and Monkey’s themes and motifs, before heading back indoors to rehearse, agreeing that he has no idea whether the production will succeed or fail creatively, while also observing: “It has been a real spiritual journey for everyone involved. And if we fail at this, it will set a lot of things back. So it’s important to me that we don’t. I mean, if it works, it could be absolutely extraordinary.”

Monkey: Journey to the West will open the Manchester International Festival on June 28

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