He came on board after seeing what his former rugby rivals Will Greenwood and Scott Quinnell had done with the British series. Kirwan is the head coach of the New Zealand branch of the School of Hard Knocks charity, established in the UK in 2008. Last year a pilot of School of Hard Knocks aired on Sky and Maori Television, and this year a full-length series has been made, following the progress of a group of disadvantaged young men from South Auckland as they try to turn their lives around through becoming involved in sport. Those spheres have come together in a television project Kirwan has been working on with executive producer Hugo Fitzsimmons.

Some fans want selfies, some just want to say hello and thank him - for both his work on the field and in the field of mental health. And the second thing you learn, during the course of those interruptions, is that despite hanging up his boots in 1999, the blond winger known as J.K. The first thing you learn when you interview Sir John Kirwan is that you can expect to be interrupted. But he still wonders if his mental health would have gotten to the stage it did if he had the tools back then to recognise what he was going through early and work on his mental health daily.Rugby might have been getting a bad rap lately, but for All Black legend Sir John Kirwan, it's still a way to change lives and give hope to disadvantaged young Kiwis, writes Sarah Ell.

Over the past few decades he has done amazing work as a mental health advocate, being knighted in 2012 for his efforts, and releasing two books, All Blacks Don't Cry and Stand by Me. If I cook in an evening it's like having an hour and a half of meditation,' he says. 'I have a very active mind and I cannot meditate, but I love cooking. The app features breathing training – the 'first tool that I use to attack my anxiety,' according to Kirwan – plus a mood tracker, worry map and mindfulness practices, which for Kirwan includes his daily shower, slow walks and cooking. The answers to that question make up some of the tools he's incorporated into Mentemia, which has been developed with a team of clinical experts headed by Dr Fiona Crichton. The next question for him then became, 'What's the ice and who's the physio?' in a mental health context. This realisation was Kirwan's 'Oh shit' moment, likening his brain to 'a hamstring in the head'.

All Blacks Don't Cry by John Kirwan