“THE sweat of a farmer, the blood of a scavenger and the footprint of a fool.” In Arlecchino, by Theatre de Complicite’s co-founder Marcello Magni, this is what the finger of fate compels the unsuspecting actor to find.

Known in English pantomime as Harlequin, the titular character is a key player in the masked theatre of Italian commedia dell’arte. Whatever the moniker, he is a vital representation of earthy appetites and impulsive mischief. Magni pays him tribute in Arlecchino while also indirectly offering both a theatrical history lesson and a master class in commedia himself.

Magni tackles his stage persona’s search for Arlecchino’s origins and anarchic spirit with imaginative zest. A bar stool serves as an instant time machine by means of which he pedals back to the Italian Renaissance and 18th-century Paris. There Magni slips between characters, quickly donning and doffing a dark, literally cheeky and curling-lipped mask. Without it, as “himself”, he is by turns dogged, enthusiastic and exasperated. But in his various guises as Arlecchino, or as a more ambiguous combination of Mercury and Father Time, he’s irresistible.

The metaphorical wall between performer and audience is handily and usually hilariously broken. The night I was there Magni turned a hirsute man in the front row into a bellowing bull. If he had less success converting a woman into a chicken, he managed to make us believe she’d laid an egg (which he swallowed raw).

Occasionally Magni hits pockets of self-indulgence. Not all his ironic asides nor some anachronisms — particularly to do with a digital camera — work. The culminating, modern-day meeting between Magni and Arlecchino falls short of a convincing pay-off. The show feels drawn out — a quarter of an hour could be shaved off it with no harm done. Nor does it quite deliver on the big ending at which it shoots. Arlecchino is still a pleasure, thanks to Magni’s gifts as an entertainer. Whether disembowelling an invisible cow, hollering across imaginary fields or simulating space travel by hand gestures and sound effects, he has the charm of a grown-up child at play. Like any quick-change artist, he combines the visceral inhabitation of a character with the confidence necessary to invent an object, action or situation out of the air. He also, you sense, truly loves the make believe magic of theatre.