The former rugby player confirmed Zara is pregnant during an interview on The Good, The Bad & The Rugby podcast on Dec. 9.
"It's been a good week for me, had a little scan last week – third Tindall on its way," Mike told co-hosts James Haskell and Alex Payne.
"I'd like a boy this time. I've got two girls, I would like a boy. I'll love it whether a boy or a girl – but please be a boy," he joked as the co-hosts groaned.
As for royal baby names, Mike pondered about naming the child after the year it was conceived, and in relation to COVID-19.
"We're not sure what to do Covi or Covina – I don't know where to go with names," he joked.
Mike also didn't reveal any clues about the baby's due date.
"We like to play our cards close to the chest," he added.
He didn't confirm which members of the Royal Family know about the forthcoming addition, but he did reveal eldest daughter Mia has yet to find out she will be a big sister again.
"We haven't told Mia yet because we knew she would tell everyone at school," the dad explained. "Now that we've gone through the scan, yes, of course we'll tell her."
Zara has previously been candid about experiencing two miscarriages following the birth of Mia. She is considered to be the first royal to have spoken out about pregnancy loss, having done so in 2018.
Mike and Zara, who is the Queen's eldest granddaughter, married in 2011 at Canongate Kirk in Edinburgh.
The Royal Family is going to have an exciting year in 2021 with a couple of babies on the way. In September, it was confirmed Princess Eugenie and husband Jack Brooksbank are expecting their first child together.
"Jack and I are so excited for early 2021....," the younger Princess of York wrote on Instagram, including a baby emoji at the end.
Two images accompanied the post. The first photo showed the hands of the parents-to-be holding a pair of baby bear slippers, with Eugenie's coral Padparadscha sapphire and diamond engagement ring visible.
Many congratulations to the Tindalls!
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