Evenings with superstars are curious things. They are either filed under “you had to be there” one-off electric menageries of collective talent, or promise a lot and stumble to deliver, like getting an invite to what you expect to be the greatest dinner party ever, only arriving to find the guests nervously pushing peas around their plates. The Abbey on Monday finds itself somewhere in the middle.

Shepard and Smith, here in support of the Abbey Theatre’s New Playwrights programme, arrive on stage with bassist and pianist Tony Shanahan, banjo player Bill Whelan and fiddle player Dermy Diamond from the Cobblestone pub in Smithfield, and Shepard’s daughter, Hannah, a rather charming cellist.

The first steps are tentative. Shepard leads the way on guitar with a bunch of American folk tunes heralding each to a halt with his cue of an outstretched left leg. His daughter executes the curious task of playing a jig melody on a cello rather well, along with a tentatively sung Óró Sé do Bheatha ‘Bhaile. Smith contributes a new track dedicated to Amy Winehouse. The audience, expecting the unexpected, and receiving it, responds warmly. There are no guest spots, although the audience is full of potentials. U2 sent a bouquet of lilies, Wim Wenders in attendance gets a shout out, and while Glen Hansard sits not too far away occasionally taking notes, Smith adds some magic to Bono’s lyrics with Until the End of the World.

The temperature eventually rises when Smith launches into Pissing In A River, every snarl, intonation and wrist flick as sharp and hair-raising as it was when anyone dropped a fresh needle on Radio Ethiopia for the first time. It’s exhilarating. At last, folks, we have a vibe.

You almost want to shoo everyone off stage to allow her the time and space to give us more. Sam Shepard’s expert reading of Beckett’s Fizzle No. 4 skips along full of humour, but when he returns to his chair, the encore Because The Night, announced sardonically by Smith as “the showstopper” is slightly impinged by his too-close-to-the-mic tambourine rattling.

With an evening bookended by Yeats readings, it’s not quite the awkward dinner party nor the effervescent cabaret. The ingredients were all there, but one can’t help but feel as though they were slightly thrown together.