So how did the rotary club pull off such a coup?
The club's community director, Don Gollan, said a few of the club's members had heard Ms Clark speak in Tauranga last year.
"We thought it's such an interesting and fascinating story from a New Zealand woman who's broken through the glass ceiling in terms of what Kiwis can do and what women can do," he said.
"You're not hearing from a person that sits at a desk in New York; she's at the coalface."
So he approached Mrs Chadwick, a Rotorua Sunrise member, for help.
Mrs Chadwick said there was sometimes an aura around high-profile people that they were "untouchable" but she simply emailed Miss Clark and asked.
"She said, 'yes I'd love to'," Mrs Chadwick said.
Mrs Chadwick said invitations would be extended to senior college students, as Miss Clark had a special interest in youth.
"I know she would want especially to inspire young women."
Mr Gollan said Rotorua people were fortunate to have the opportunity to hear from a person of Miss Clark's stature.
She oversaw an international budget of $5 billion, rubbed shoulders with world leaders and was responsible for programmes in 189 developing countries.
He said the evening would be like having Miss Clark and Mrs Chadwick in your living room - Steiner Interiors will set up couches on stage for the two women leaders. The audience will have the opportunity to submit written questions, and a selection to be put to Miss Clark by the MC.
Politics and election talk will be off the discussion agenda though. Miss Clark had "moved on" from New Zealand politics and "never goes there", according to Mrs Chadwick.
Tickets are $30. For an extra $55 people can also attend a supper after the talk, attended by Ms Clark. All proceeds will go towards the club's Rotorua youth projects. Tickets go on sale on Monday from www.ticketmaster.co.nz or from the Rotorua Convention Centre.