Singing and acrobatics – in Norwich Cathedral: I saw it on paper and, just for a second, raised a distrustful eyebrow. After all, such is the craze for ever-wackier inter-disciplinary events, that it's all too easy to be cynical. Not that there's anything wrong with cross-pollination in itself. But it carries certain risks. You could wind up with a dog's dinner: a mish-mash of disparate components that serve only to detract from one another (something along the lines of Michel van der Aa's recent 3D opera Sunken Garden.) Or you might get a non-entity, piggy-backing on the strength of sheer novelty value and hype.
   
Or you might just be lucky, and stumble upon something like 'How Like an Angel', performed last week as part of the Norfolk and Norwich festival. This sold-out event – a collaboration between the vocal ensemble I Fagiolini and contemporary circus troupe Circa – was a reminder that fusing eclectic art forms can and does work. And not just because everybody likes to see a good cartwheel.
   
The venue certainly helped: as rain pattered down from the darkening sky we were led through the cloisters into Norwich cathedral, where we were left in silence to soak up the atmosphere. Then, just as we began to wonder whether anything was going to happen, we heard the sound of disembodied voices, artfully scattered across the space: just one to begin with, then another, and another, and another. Tiny melodic shards collided in discords before assembling into a gleaming rendition of Thomas Tallis's Gaude gloriosa – a work devoted to the Virgin Mary – that resonated beautifully in the cathedral's generous acoustic. I'd have been satisfied just with that. But then the acrobats set to work, with a tremendous display: physical contortions that defy laws of biology, human pyramids, nail-biting balancing acts etc - all woven into an exquisite choreography. 
   
But what really stood out, however, was just how well it was integrated with the singing. It's one thing to watch someone soar from the ceiling, suspended only by one ankle. Or to gawp as she stretches and twists her body into the most unlikely of shapes – like a human cat's-cradle. It's another to hear it reflected so aptly in the music: the celestial sweep of Victoria's Alma redemptoris mater; and the knotted lines of Hildegard von Bingen's O viridissima virga. The rhythm of the pieces flowed seamlessly into the movements, and moments of musical tension and release were perfectly timed to match those in the choreography. Admittedly, these works had never made me think of acrobatics. After watching this, you'd almost have thought they were written for the circus. It was like watching a ballet, but one with disturbingly high stakes: when the artists finally came down to safety for their bow, our collective sigh of relief bounced off the walls.
   
To me, this was a model of a successful inter-disciplinary performance – where each element worked perfectly well in isolation and even better when combined. I would have come for the singing or the circus alone. Together they added up to more than the sum of their parts.

'How Like An Angel' will also be staged at Salisbury Cathedral as part of the Salisbury International Arts Festival from June 6-8, and at St Bartholemew the Great in London from June 25-28.