Why Am I So Single? at the Garrick review: crackerjack show proves Six creators are no one-hit wonders

This new musical from the creators of the pop-feminist, Tudor-history hit Six is just as quirky and surprising and almost as good.

Having yassified Henry VIII’s wives, Toby Marlow and Lucy Moss here turn inward, with a clever, larky, exuberant examination of their friendship and disastrous dating history: she as a straight woman, he/they as a gay trans man whose pronouns change according to his/their mood.

The score works its way sassily through genres from diva numbers to dance music and the lyrics are elegantly witty and laced with f***s.

There are at least two solid gold bangers, Just in Case and Disco Ball, a gorgeous tap routine that references the tap and swipe of dating apps, and a pastiche of Who Will Buy from Oliver!, where snippets from Hinge profiles combine in a rich stew of cockiness.

The writing duo’s shared love of Lionel Bart’s classic is a theme throughout: their onstage avatars are Nancy (Leesa Tully) and Oliver (Jo Foster), and their agent is called Faye Ginn.

For this is a meta show that flirts heavily with self-indulgence. Nancy and Oliver embark on their navel-gazing self-analysis partly to escape the burden of writing a new “big, fancy musical” to match the surprise success of their first.

There’s little plot, just repeated explorations of the titular question across 19 songs. The fourth wall is regularly broken with eye-rolling asides and the whole thing is riddled with irony.

Aware they can’t end Act I on the anthemic Just in Case, the score spirals off into a frenetic, classical pastiche about a bee that distracts and terrifies Oliver and Nancy. The constant reprises lead to a second-act number called Why Am I Still Reprising

The writing duo’s millennial quirks and prejudices litter the script, from jobs in finance and LinkedIn profiles as romantic red flags to an obsession with the Friends finale.

A further smart joke is that this big musical about writing a big musical takes place in one room of Oliver’s flat, with past nightclub encounters and parades of lovers conjured up by an ensemble cast who otherwise do duty as a fridge, dustbin, hatstand, and exceedingly camp cheese plant.

Shout out here to Max Johns’s costumes, which include a skirt and sweatshirt for Oliver that transform into a Marilyn Monroe ballgown, and a jumper that gives Nancy an anatomical heart on her chest, rather than her sleeve.

The cartoonish set by Moi Tran (with the visible band above) and the hectic direction by co-writer Moss and Ellen Kane, who also supplies the energetic choreography, contribute to a sense of fizzy fun edged with desperation.

Tulley and Foster’s voices initially lack body but mature and grow movingly throughout the evening. Noah Thomas exhibits easy charm and loose-limbed grace as their friend Art Fulldodger (groan).

It’d be impossible to replicate the alchemy of Six and it’s wise of Marlow and Moss not to try. This zesty, in-jokey, crackerjack entertainment proves they’re certainly not one-hit wonders.

Garrick Theatre, booking to Feb, nimaxtheatres.com