The former rugby player previously admitted he met a lot of Zara's family through Sunday lunches and watching rugby matches at home, but he was introduced to one royal almost two decades before.
On The Good, The Bad & The Rugby podcast, Mike pointed out a photo of his school and recalled: "This school was founded by Queen Elizabeth I. The 400th anniversary in 1991, Queen Elizabeth II came when I was 13 years old. Think I met her in biology."
While it would be 19 years before he walked down the aisle with the late Queen's granddaughter, he joked: "Not entirely sure whether I said to her then that I would marry Zara, but it might have come out of my mouth."
Mike had previously got emotional when reflecting on his limited time knowing his grandmother-in-law. When his podcast co-stars asked if he realised how lucky he had been to spend one-on-one time with the Queen, he replied: "I do. But I also have loads of regrets.
"Loads of regrets about not asking her so many more things. Having nervousness when you sit down to talk… that lucky seat and being sat next to her."
The 45-year-old father-of-three first crossed paths with the Olympic equestrian during the 2003 Rugby World Cup in Sydney. Following a "boozy" first date, their relationship developed and Mike was gradually introduced to the royal family, with whom he now has a close relationship.
"We'd go on a Friday night to watch the match and stop over at Zara's," he told the Sunday Times Magazine. "Sometimes we'd all go out for lunch with Zara's mum on Sunday before we went home. We spent quite a bit of time with her dad too. Prince Harry would often be round watching the rugby, so, slowly and quietly, we got to meet them all – and that's how it went on for quite a few years."
Speaking about the "incredibly relaxed" meeting between his parents and Zara's, he added: "Mum and Dad met Princess Anne early on. And it was incredibly relaxed. Zara was living in a little two-bed flat in Nailsworth, so it wasn't exactly grandiose."
The couple got engaged in December 2010 at their Cheltenham home. Mike organised a "shock value" proposal during a movie night at home and presented his bride-to-be with a split shank diamond engagement ring thought to be worth £140,000.
They exchanged vows on 30 July 2011 at Canongate Kirk in Edinburgh, with Zara stepping out in a stunning ivory bridal gown by Stewart Parvin, one of Queen Elizabeth's favourite couturiers. They then joined friends and family for a wedding reception at the late Queen's official Scottish residence, the Palace of Holyroodhouse.