"Well, the formal address is 'Your Excellency' but my name is Catherine."
He put his arm around my shoulders as we walked back to the terminal - and thereafter called me Cathy. What a lovely man he was. He quite enchanted everyone he met with his natural manner and simple charm. I was more in awe of him than of any of the queens, kings and presidents I had ever met.
He and his daughter and a few of his entourage lived in the house while the others went to a hotel. His staff were very protective and set stern rules. For instance, no flashlight photography. His sight had been damaged by the lime dust from the stone-breaking work during his many years of hard labour on Robben Island.
The next night, we had a state dinner at Government House. Earlier in the day I had asked him if he would come, with his daughter, to my sitting room before the dinner so that my family could meet him privately.
My daughter, Judith, had invited Philip Kirk to be her partner and, when he was identified as Norm's son, Mandela lit up and surprised us all with his knowledge of who Norman was and the role he had played in New Zealand politics.
I asked him how he could speak so forgivingly about his own history. "Oh Cathy," he said, "you can always forgive - but don't ever forget."
He was asked if he was aware of the events surrounding the 1981 Springbok tour of New Zealand and its consequences. "Oh yes," he said. 'By that time we were allowed to have newspapers in prison and were incredulous that a peace-loving people on the other side of the world would stand up against their own police for our cause."
And he paused. "I will never forget the day the Hamilton game was cancelled." He paused again. "It was like the sun coming out."
We gasped to think he even knew of Hamilton. I think everyone in that room came out in goose-bumps - I know I did.
I made sure that all the people who had been leaders in the anti-tour activities had the opportunity to shake his hand.
On the way out, I stopped to introduce Ralph Hotere, a very shy man, who gave Mandela a souvenir of a screenprinted scarf he had designed in honour of Steve Biko after he died. Our guest was very touched and gave it to his daughter to look after.
It was, without doubt, the most wonderful encounter of my life. Except in public, he continued to address me as Cathy. I never called him other than Mr President.
I said farewell to him with genuine regret as I knew we were unlikely to ever meet again.
As it happened, I toured South Africa 10 years later with friends willing to try to make a contact for me but it was at the time of South Africa's bid for the Football World Cup which Mandela was fronting and he was out of the country.
We went to Robben Island, which is now a tourist spot, and it was moving and humbling to see where this amazing man had spent 18 years of his life.
We were but ships that pass in the night. But, oh my, what a mighty and unforgettable ship he was.
