Hatty is 29 years old and works in advertising. When one of her housemates gets engaged, she and best friend Poppy prepare to move into a new place together. Except Poppy’s just got a new boyfriend, whereas Hatty is still single, bored with her job and suffering from frequent bouts of anxiety – all of which is a far cry from her glamorous past as a child movie star.

Written by and starring Hatty Jones, That Girl is the story of a young woman who still hasn’t quite figured out who she is or where her life is going. Based on the writer’s own experience as the star of 1998 children’s movie Madeline, it examines how this early fame continues to affect her as an adult, long after giving it all up in favour of a “normal” life.

Although Hatty the character has the same backstory as Hatty the writer, it’s not clear how much the two now overlap – though it does seem unlikely that the Hatty on stage would allow herself to be portrayed the way we see her. Insecure and needy, this Hatty is unable to celebrate even her best friends’ successes and, despite her protests to the contrary, only really comes to life when given an opportunity to relive her childhood fame.

Even these opportunities aren’t as frequent as she’d like everyone to believe, and it’s often Hatty herself who brings up the subject, shoehorning her early success into conversation by any means possible. It’s clear that her memories of Madeline are a comfort blanket, a reminder of a time when life was exciting, and a stark contrast to her current mundane existence. These days, she’s just like everyone else – a young woman approaching her 30th birthday, watching her friends settle down with boyfriends and mortgages, and panicking about being left behind. While we’re able to relate to her motives, it’s difficult to approve of her methods as, in her desperation to hold on to her lifelong friendships, she ends up putting them at risk.

Whatever our feelings about the character, it’s difficult not to warm to the real Hatty Jones, who makes a powerful playwriting debut with That Girl, and also gives a thoroughly engaging performance as “herself”. She’s joined by fellow cast members Alex Reynolds as Hatty’s colleague Lola and housemate Poppy, and Will Adolphy, who plays Poppy’s boyfriend Adam and Hatty’s date Dylan. Both actors move seamlessly between their two characters with just a quick change of outfit, to show us a cross-section of the people that make up Hatty’s world – a superficial world of Tinder, bloggers, avocados and brunch.

Directed by Tim Cook, the action moves at a steady pace as we follow Hatty over two days. They’re not particularly eventful days – which is sort of the point – but that certainly doesn’t mean there’s a lack of tension. With cardboard boxes scattered around Sunny Smith’s set, we’re constantly reminded of the impending move and the pressure it’s placing on Hatty and Poppy’s already strained relationship. This eventually comes to a head after a deeply uncomfortable moment between Hatty and Adam, which is so well written that it feels like watching a car crash in slow motion; we know what’s coming, but can do nothing to stop it.

Simultaneously funny and heartbreakingly sad, That Girl is a very relatable story about fame, friendship and the pressures of adulthood. Madeline may be all grown up, but if this play is anything to go by, her adventures aren’t over yet.