A one-woman show is a herculean task. Recent attempts, like Cynthia Erivo’s solo performance of ‘Dracula’, or Sarah Snook’s ‘The Picture of Dorian Gray’, have sustained the dramatic interest by harnessing the possibilities of 21st century staging with gymnastic camera work, pre-recorded footage and other dazzling multimedia effects.

In Age is a Feeling, Haley McGee relies on none of these supports, instead delivering a stripped-back, confessional and cuttingly-comic solo exploration of the process of ageing.

The intense vulnerability of this Olivier-nominated play must be even more difficult to shoulder in the immense, 1000 seat cathedral of the new auditorium at Soho Theatre Walthamstow, a far cry from its fringier, compact hub in Soho.

The only staging to aid McGee comes in the form of a tall wooden seat – akin to a lifeguard chair – surrounded by a fortune’s wheel of flowers, each representing a different story of the character’s life. Some of these stories will be heard by the audience, some of them will be left untold – the audience gets to choose.

Instead of becoming a gimmick, it serves McGee’s thesis on the fragmented, unknowable nature of life: ‘You don’t get to know everything, and no one gets to know everything about you, not even yourself.’

The play begins on the character’s 25th birthday (so young!), and from there McGee reflects the pains and fears of ageing with extraordinary wit and lyricism, her comic delivery no doubt refined from the show’s prize-winning run at Edinburgh Fringe.

‘You’ll stare at your reflection’, she says. ‘In some horrible kaleidoscope of a fitting room aghast to see your mother’s bum attached to your body.’

Observations ruthlessly shift from laments on body changes (‘Nobody warns you that your teeth shift – well, your teeth shift!’) to anxieties on family, so enhanced in the modern world: ‘From afar, you’ll watch your friendships couple off. Babies will be born, by choice. By design.’

The laughs come thick and fast, but so do the groans of realisation as the audience have so many truths reflected back to them. The stories, and the interludes between them, cover such a remarkable amount of ground that everyone will have something resonate: a rejected proposal, the death of a parent, the attempted suicide of a friend, the urgent need for a baby, the guilty envy of a friend who is ‘prettier, faster and more accomplished.’

There does, however, come a point in the play when you realise that this play is not biographical, and for a moment the stories and reflections of an age not experienced by the actor lose that power of reality.

But this is short-lived. Because McGee enacts them with such clarity and depth that the fictional journey, from 25 to the moment of death, feels completely real.

That inexorable movement towards death is felt heavily towards the play’s climax. In her 60’s, she pushes ‘back death with medication and meditation’. In her 90’s, her body ‘becomes a medical specimen.’

And by far the most powerful scene comes in a magical moment of catharsis when the character’s partner dies, and the dialogue and movements of Mcgee are performed with a delicacy that is so moving that it brought someone near me to tears. If McGee’s talent wasn’t clear already, it certainly was here as not just a comic but also a tragic actor.

The meaning of ‘Age is a feeling’ changes throughout the play, and it is not just at the close of it that the hopeful, lighter meanings of that title become apparent. You leave the theatre not with a feeling of despair, but with a renewed appreciation of mortality: ‘You have all this to come, and things only you knew will die along with you.’