There is no way to understand how JM Synge’s 1907 classic comedy caused a riot at its first performance. The “playboy” Christy Mahon, so brave that he’s killed his own father, or at least “laid him low with a loy” says that he’ll stand by his resolution to marry only the girl of his dreams, Pegeen Mike.

Nothing will divert him, not even “a drift of Mayo girls standing in their shifts itself.” The first audience broke up in disorder at this supposed insult to Irish womanhood, but you’d hardly raise an eyebrow with the phrase now, and Robert Sheehan’s surprisingly tall and energetic Christy uses it merely to inflate his own idea of himself.

It’s a lovely play, and John Crowley’s Old Vic production doesn’t try for anything fancy with it. In truth, it’s a bit flat in parts, but Sheehan, while he doesn’t have the overlarding comic charm of Cillian Murphy in the role (the last great playboy, for the Druid Theatre Company) or the accumulating swagger of Stephen Rea many moons ago, is perfectly beguiling and watchable.

And he’s very well matched on the stage with Niamh Cusack’s delightful Widow Quin and Ruth Negga’s brazen Pegeen Mike, a real advance for this actress on her Ophelia at the National Theatre. It would be impossible to produce a Playboy that didn’t look as it should, and Scott Pask’s remote country shebeen, crowded with local characters and melancholy music-making is bang on the money.

What do we now take from the play, apart from the glories of the language, the famous Synge song of the prose? Like Gogol’s The Government Inspector, The Playboy of the Western World paints a portrait of someone creating an identity for himself in the misguided credulity of others. Christy’s a nonentity suddenly imbued with a character, living a fantasy life in a community that succumbs to its own need for heroes.

No other comedy in our language so beautifully creates, and then punctures, this myth, and it’s wonderfully ironic that two of our newest shooting stars at the high end of the celebrity stakes – Sheehan and Negga – should take up the challenge of reasserting the full value of common humanity in a world spinning out of control, reverberating with political lies and vain boasting.