You've probably heard this piece of advice dished out to a nervous performer before: to relax, picture the audience naked. Last week, however, actors Maev Beaty and Erin Shields went one step further – and actually performed in front of a naked audience. In what may be a theatrical first, they held a special clothing-optional performance of their play Montparnasse at Toronto's Theatre Passe Muraille.

"I would say the advice should probably be rewritten," Beaty joked to me over the weekend, confessing that, rather than relaxing her, all the naked flesh reflecting the footlights briefly made her self-conscious. "It was like a whitey-pink wall facing us. It was incredible." Since the end of the 1960s, nudity has been a fairly common sight on stage, from Hair to Ian McKellen's King Lear. Nudity in the audience, however, has remained the kind of thing that gets you arrested – as Pee Wee Herman learned.

Thursday night's groundbreaking performance of Beaty and Shields's acclaimed two-woman show about nude life-models in 1920s Paris was the result of some creative thinking about how to get bums in seats – literally, as it turned out. Wanting to reach out beyond Toronto's usual theatre-going crowd, Groundwater Productions and Theatre Passe Muraille targeted all sorts of niche audiences: models, art students and, by programming two performances with American Sign Language interpretation, the city's deaf community.

But the most unconventional idea was the brainchild of producer Gideon Arthurs: since Montparnasse is such a flesh-friendly show – the two actors are frequently nude as their characters pose for the likes of Picasso, Chagall, Pascin and Soutine – why not invite naturists to a private performance? Bare Oaks Family Naturist Park helped the theatre company out by creating a Facebook group, and soon naturists were buying tickets from as far afield as Ottawa, Ontario, and across the border in Buffalo, New York.

Eventually news of the clothing-optional performance leaked out to the general public on Twitter, where many mistook it for an early April Fool's joke. "Seriously? Who's paying to steam-clean the chairs afterwards?" tweeted local dramaturge Toby Mallone aka @shksprn. (It turns out that naturists don't want to sit their naked bottoms down on dirty, public theatre seats either. "It was a BYOT event – bring your own towel," Beaty explained to me.) Judging by the comments made to the actors and online, Thursday's naturist spectators – atypical not only because they were nude, but because they were 80% male and not regular theatregoers – really appreciated being made to feel at home.

And that's ultimately the lesson others independent theatre companies may want to take from Montparnasse's experiment. As the near-capacity crowd proved, reaching out to non-traditional theatregoers – nudists or not – is a smart move. What other untapped, if not necessarily undressed, groups are out there just waiting to be welcomed into the theatre?