Winner of the most outstanding show award at this year’s Melbourne International Comedy Festival, as well as the Golden Gibbo prize for pursuing artistry over commercial gain, Gillian Cosgriff marvels that near-universal acclaim for the uplifting Actually, Good hasn’t quelled her performing insecurities. ‘Oh, not less imposter syndrome: more! We’ve doubled it!’ the musical comic wryly observes.

Only with a concerted effort from her ‘speedy, anxious little brain’ has the outwardly chipper Australian convinced herself that ‘everyone is not just being nice to me now; there’s evidence I should trust myself and keep going.’ Arriving in Edinburgh, with the tailwind of a hit hour for the first time, makes it a ‘tiny bit’ less daunting, she says. ‘But not much less so. It’s still a big deal.’

She recalls her 2016 Fringe debut. ‘I was like, “listen up self. Get $10,000. Burn it. No one’s gonna come. And if they come by accident, they’ll hate it.” I beat myself down to a very low level. However, it was an unseasonably warm year and I had quite a nice time.’ The next year, Cosgriff had a more typical Edinburgh experience. ‘More challenging and soul-destroying in all the ways that it can be,’ she grins. ‘We talk about it a lot on the Australian scene. It’s such a big journey for us, geographically if nothing else. The only thing you know is that it’s going to make you better. Rather than thinking about my soul and my art . . . well, calling it boot camp is too aggressive. It’s a heightened training environment.’

Tentatively approaching comedy again for the first time in five years, following a lockdown-prolonged spell in the stage show Harry Potter And The Cursed Child (playing the phantom Moaning Myrtle and villainous lead Delphini), Cosgriff had passed a wretched, rain-soaked holiday with her partner in which they invented a game listing ten things they liked and loved. Having started to ask mates for their own top ten lists and putting them in her phone with some other ideas, she sat down with a friend in November to try to figure out what her stand-up return might be.

Cosgriff recalls the conversation: ‘“A lot of this is a big fear salad,” she said, “you’re very afraid of things.” But as I’d asked her for her ten likes the day before, she explained that I’m also a very positive person who picks things up and goes, “look at this! Isn’t this amazing?” She was like, “that’s your show!”’

Having long performed improv as a sideline, Cosgriff also began chatting to audience members during her show, then writing a song for them. ‘I enjoyed that rapport,’ she explains. So it felt natural to ask crowds for their little loves, building an inclusive feeling to Actually, Good while keeping it fresh for her night after night.

‘It is remarkable what people will tell you when you have a microphone,’ she laughs. ‘I’ve been very fortunate in how generous they’ve been with their suggestions. And it’s a gift; you can do so many callbacks. You still don’t quite know where it’s going to go though, so it’s still a little terrifying and beautiful in that respect.’

She shows me the chunky, rather ornate book in which she now records the lists that she’s given, looking (appropriately enough for Edinburgh) worthy of a spell-casting boy wizard. Speaking of which, Cosgriff spent much of lockdown absorbing storytelling virtuosos Daniel Kitson and James Acaster. And from 2020 she had the ‘absolute privilege’ to direct Michelle Brasier’s show Average Bear, studying how these music-loving acts structured their shows, the threads that would ultimately ‘tie together into a bow’. It might be expected, then, that she’d deploy her songs as ‘building blocks’ for her hour; instead, they serve as ‘underscore’. Currently developing a musical, The Fig Tree (named after the metaphor of choice in Sylvia Plath’s The Bell Jar), she cites Australian singer-songwriter-comedians-turned-stage showrunners Tim Minchin and Eddie Perfect as her career templates. ‘I’ve always wanted my shows to feel like you’ve come to my house for a dinner party,’ she explains. ‘We’ve eaten everything, we’re having the last bottle of wine or whisky, I’m sat at the piano, noodling, and we’re all just having a chat, rather than a big production spectacular.’

But Cosgriff isn’t always comfortable sharing her opinions. ‘I feel like I’m always trying to figure something out,’ she reflects. ‘I treat my mental health like I’m a detective when something bad sets me off.’ However, by crowdsourcing the tiny delights of others, ‘I get this beautiful experience where I remember them all,’ she explains. ‘The other day I was driving in the rain and went under a bridge. And you know how it’s quiet for a second? I was like, “ah, my dad. Number six.”’

In fact, she’s essentially rewired herself cerebrally. ‘Evolutionarily, we’re made to look for threats because it’s helpful to your monkey brain to stay alive,’ she suggests. ‘But as a comedian, you’re constantly poking the world to see what falls out. Is this a joke? What if I turn it this way? Or say it three times? Because of this show, I’m poking the world for good stuff. I came home from tour the other day and happily thought about having a whole row to yourself on a plane. Or walking briskly on a travelator.’

When a friend’s boyfriend recently suggested ‘skies that look like Renaissance paintings’ in his top ten list, Cosgriff judged him worthy of her. ‘I’ve weaponised my anxiety so that it doesn’t just remind me of every embarrassing thing I’ve ever said, but also every nice thing anyone around me has ever said. It’s lovely.’

Gillian Cosgriff: Actually, Good, Pleasance Courtyard, until 27 August, 8.20pm.