Over more than a decade, he has initiated one-on-one encounters that found him listening to strangers in an exchange of personal confidences and even washing his audience. In the early years he approached these intimacies as his alter-ego Adrienne, a wonderfully garrulous broad who was a dab hand with the red lippy, loved a glittery bit of bling and had the legs for a denim mini-skirt.
More recent projects, however, have seen Howells move towards an even greater degree of openness and vulnerability. Adrienne is now in a prop box and it's Adrian, sometimes in a suit, sometimes in casual sweats, who does the rituals of foot washing or, as so successfully on last year's Fringe, the whole process of Washing, Feeding, Holding.
When it comes to his new piece, Lifeguard, he is almost lost for words. Tonight at Glasgow's Govanhill Baths, Howells will strip down to his Speedos and plunge into a performance that truly measures up to the current theatre buzzword: "immersive". There is water in the pool, and Howells, along with fellow performer Ira Mandela Siobhan, will be in it.
"I keep asking myself, why are you doing it?" Howells has just finished a hard day's swimming and is in need of hot food and a restorative coffee. He's joking about the muscle twinges and chlorine-dried skin you don't normally associate with rehearsals. And he's still clearly a bit bemused by the fact Lifeguard is, indeed, about to open for a three-week run. "Here I am, I'm 50. I'm getting into a pool with a man half my age who is totally fit; a wonderful dancer who moves through the water beautifully. And people are going to be watching. So yes, I'd say I'm feeling very exposed. This is not what I expected I'd be doing at 50. When I looked at the direction my work was going in, I envisaged more of a slowing down process and going towards a kind of calm. Now I'm wondering if Lifeguard really is such a departure from what I've been doing. It's different, but I'm seeing more connections with my previous solo shows as we get deeper into exploring the relationship we have with each other, and with the water."
As he starts mulling over the layers of circumstance and experience that prompted him to create Lifeguard, it soon emerges that – as with all his previous work – the initial impulses are rooted in his own life and psyche. Since childhood, Howells has loved being in the water, and swimming pools especially.
"I just loved watching other people," he says, "and the way we were in a safe place, but people could get into difficulties – maybe even drown. So there was this thrill that it was dangerous as well as fun. And that paradox intrigues me even more as an adult."
His own role in the new work is that of a lifeguard, Siobhan is the swimmer. Though Howells says they have resisted making it a linear narrative, he reckons the imagery of Lifeguard carries its own little stories, its own comments on relationships, change and risk.
The notion it would play to a pool-side audience, rather than be a one-at-a-time ticket, gained momentum after a working trip to Singapore where he witnessed the bonding warmth of cross-generational communities. Supported by the National Theatre of Scotland in co-production with The Arches, Howells gained access to the training pool at Govanhill Baths, and the sense of a community coming together in a common cause – restoring the disused pool – clinched it for him.
"Audience numbers are limited," he says. "But we really want people to feel a part of our community while they're with us." On the practical side, that means turning up early and changing into something appropriate, like a swimming costume or shorts and a top. "There's every chance you're going to get wet even if you don't get into the pool at some point. But I never, ever, ask anybody to do anything they're not comfortable with. So there's no pressure to strip down to a bikini or mankini, I promise."
For Lifeguard he's been able to work with a creative team that includes composer Nichola Scrutton, choreographer Jane Mason and film-makers Minty Donald and Nick Millar.
"We wanted Lifeguard to remind people of the part water plays in our lives," he says. "And the other elements – sound, lighting, film and movement – help show how much we rely on water for our life, but also how water can be a deadly and destructive force.
"We're made of water; it's seven-tenths of our bodies and our world is seven-tenths covered by it. Those thoughts are a part of Lifeguard. So I think: you're 50 now, Adrian, and if you don't do this now ... Well, when are you going to make a splash?"
Lifeguard opens tonight at Govanhill Baths, Glasgow, and runs until October 27. Visit www.thearches.co.uk.