If the baby is male, it will mean Princess Anne will be a grandmother to a boy for the first time. All of the Princess Royal’s grandchildren, including Ms Tindall’s current kids Mia and Lena, are girls.
Zara and Mike Tindall have not publicly revealed whether the upcoming baby is going to be a boy or a girl.
Speaking on his The Good, The Bad & The Rugby podcast, sports star Mike said the couple are expecting a new child in December last year.
He told co-hosts James Haskell and Alex Payne that there is a “third Tindall on its way”.
She also offered to help teach the two children during last year’s coronavirus lockdown while they were being homeschooled.
Princess Anne has been described as a notoriously private member of the Royal Family and a busy one.
She recently attended the Oxford Farming Conference, for which she is Honorary President, this year via video link.
Meanwhile her brother Prince Charles has also been busy so far this year, having attended an international climate conference this week.
Speaking French to delegates, Charles urged companies to support the new ‘Terra Carta’ climate change initiative.
Speaking to news outlet CNN that same day he warned the world faces even more pandemics if climate change is not tackled.
The Prince of Wales said: “What good is all the extra wealth in the world, gained from ‘business as usual,’ if you can do nothing with it except watch it burn in catastrophic conditions?”
The Terra Carta scheme aims to raise $10 billion worth of investment by next year.