The star of British television quiz show The Chase, also known by the nickname of "The Dark Destroyer", was in Dunedin to host a quiz evening at the town hall, which was raising money for the Louise Davie Charitable Trust.
But before that he managed to watch the All Blacks squeak out a 16-15 victory against England at Forsyth Barr Stadium on Saturday.
He signed a copy of his autobiography Chasing the Dream for Robertson.
"It was a great first victory for him and long may it continue.
"It’s the first time I've actually seen the All Blacks play in New Zealand, so that was fantastic — I was actually at the World Cup final [in France] last year, because I'm a huge fan of Sam Whitelock, and I wanted to see him become the first player to win three World Cup finals.
"It wasn't to be, but he was so gracious in defeat."
Wallace said he practised for several hours before each episode of The Chase, which included watching old clips.
"I'm a perfectionist, so I tend to only focus on the questions I got wrong.
"You have to have a willingness to learn, and look for the clues in each question, because there are always clues, particularly if you're a linguist."
The Otago Daily Times decided to test Wallace on a special online quiz.
Wallace acquitted himself well — only stumbling on questions about the founder of the ODT (Sir Julius Vogel) and fittingly, the word no longer said by a rugby referee at the beginning of a scrum ("touch").
He said he rated all of the other chasers, but particularly enjoyed watching Paul "The Sinnerman" Sinha and Anne "The Governesss" Hegarty.
"I also really like Mark ‘The Beast’ Labett’s reactions when he gets something wrong."
It was a combination of the chasers’ different personalities and host Bradley Walsh’s humour that was the secret of the show’s success, he said.
Wallace said he would spend the next few days travelling the country hosting quizzes for various charities.
He was a frequent visitor to New Zealand, and enjoyed people coming up for a chat.
As to whether The Chase might film a special episode in New Zealand, Wallace said "that’s above my pay grade and out of my hands, but never say never".
All told, it was just another day at the office.