What started out as an idea to do a year-long, fly-on the-wall style film about former Prime Minister Helen Clark turned out to be a documentary about an historic process.

Renowned Kiwi filmmaker Gaylene Preston's film My Year With Helen became a study of gender politics and an insight into the closed world of international diplomacy at the United Nation, at a time when the UN was claiming to be transparent in its appointment of its 9th Secretary General. 

Helen Clark, who'd been running the UN Development Programme for more than seven years, was vying for the top UN job, but ultimately lost out to former Portuguese Prime Minister Antonio Guterres.

He became the ninth man to be appointed UN Secretary General - there has never been a woman in the job.

Wallace Chapman spoke to Helen Clark and Gaylene Preston about the film and the process of making it.

Watch below: