Mike Tindall Clarifies What He Calls Princess Anne, His Mother-in-Law, in Private

"M'am, not Mum!" said the retired rugby star, who is married to the Princess Royal's daughter, Zara

Mike Tindall knows just what to call his royal mother-in-law, Princess Anne.

On Nov. 4, the retired rugby star made the revelation while appearing on Good Morning Britain to discuss his new book, The Good, The Bad & The Rugby – Unleashed: The hilarious new sports book, which was published in the U.K. on Oct. 24.

Mike, 46, is married to Princess Anne's daughter, Zara Tindall, and Good Morning Britain presenter Susannah Reid asked him at one point during the segment, "What do you call her, Princess Anne?"

"M'am," Mike replied with a chuckle in a video shared by the Manchester Evening News.

"Not Mum, M'am," interjected James Haskell. Mike, Haskell and Alex Payne co-wrote the new The Good, the Bad & the Rugby book, named after their podcast of the same name that they launched in 2020. 

Related: Mike Tindall Says Marrying Into the Royal Family ‘Was Pretty Easy for Me’

"M'am, not Mum," Mike repeated, and Haskell joked, "After a few beers, you probably call her that."

After seven years of dating, Mike and professional equestrian Zara got engaged in 2010 and married in 2011, making him officially part of the British royal family. The couple went on to welcome three children, daughters Mia, 10, and  Lena, 6, and son Lucas, 3.

Though Zara is not a full-time working royal like her cousin Prince William, she and her husband are often spotted at the royal family's formal and informal events, from King Charles' coronation to Royal Ascot and holiday church outings. The Princess Royal, 74, and her son-in-law seem to be at ease in each other's company, and have shared many chats and laughs on the sidelines of Zara's equestrian competitions.

Related: Meet the British Royal Family: A Complete Guide to the Modern Monarchy

In September 2023, Mike and his podcast co-hosts had three VIP guests on the show — Princess Anne, Prince William and Kate Middleton! The special episode was timed to the start of the 2023 Rugby World Cup, as Prince William, Princess Kate and Princess Anne are the respective patrons of the Welsh Rugby Union, the Rugby Football Union (of England) and the Scottish Rugby Union.

The memorable episode was full of upbeat moments, including Mike mentioning that Princess Kate brought the heat in beer pong and Princess Anne weighing in on whether Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6, were competitive like their parents, the Prince and Princess of Wales.

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The show, filmed at Windsor Castle, was a rare joint media appearance for Princess Anne, Prince William and Princess Kate, and Mike later reflected in The Good, The Bad & The Rugby – Unleashed that their conversation in full would have "blown the public away."

"I think the podcast humanized them a little bit, and I kind of wish they’d let us put the uncut version out, because it would have blown the public away," Mike wrote in the book about the exchange with William and Kate, according to an excerpt published by the Daily Mail on Oct. 24. "It was a far more enlightening chat than I expected, not because I thought they'd be dull (I already knew that they weren't), but because I know how everything to do with the royal family is so carefully controlled,"