‘An actor can do anything they want – as long as they mean well when they do it.” Such, jokes Chris Grace, was the movie star Scarlett Johansson’s justification for starring in manga adaptation Ghost in the Shell in 2017. Grace, an Asian-American actor and comic, stress tests that philosophy here with this mind- and character-bending comedy hour in which he stars as Johansson (who in turn stars as Chris Grace, and so on …). It’s a great device, embedding Grace’s ideas about cross-racial casting into the structure and playful humour of the piece – at least until the end, when (please stop!) he starts spelling the argument out. That’s his prerogative: the debate isn’t academic for the 50-year-old, who’s been pushed to the margins his whole showbiz career – as a few dismaying anecdotes demonstrate. It’s also a function of the recursive structure: Grace’s show keeps re-starting throughout the hour, as the joke about Chris-playing-Scarlett-playing-Chris adds another layer. So perhaps it requires multiple false endings, too. In a few of which, even if I worried Grace was over-articulating, he does add some complicating footnotes to the case the show has made. You won’t leave thinking there are easy answers to the “whitewashing” question. But your mind will be buzzing at the thought of it all, and you’ll be tickled all over by the intricacy and deadpan drollery of Grace’s construction, which parallels his own biography with that of his movie-star alter ego, then collapses both into something wilder, as the very ideas of authenticity and fixed identity come under high-kicking, Black Widow-style attack. It’s just silly, too, with Grace teetering under a tower of wigs, squeezing himself into superhero costumes – and having his moving finale heckled by his own voiceover. In a show that premiered in the US, there’s also plenty of material fresh-minted for Edinburgh audiences, including a gallows-humour purler about the phrase “sweet Fanny Adams”. Grace ends the show torn between cautious optimism and the thought (a haunting image, this) of his Chineseness as a mask he can never remove. It’s rich, this show, it’s complex – and it’s knottily funny. At Assembly George Square, Edinburgh, until 28 August All our Edinburgh festival reviews