Buckingham Palace released a short but sweet note that read: "The Queen and The Duke of Edinburgh are delighted with the news and look forward to meeting their 10th Great Grandchild when circumstances allow."
Her Majesty and the Duke have been based at Windsor Castle during the pandemic, while Zara and Mike live on Princess Anne's estate, Gatcombe Park, in Gloucestershire, which is about a two-hour drive away.
WATCH: Mike Tindall announces birth of baby boy
Proud dad-of-three Mike announced the news on his podcast, The Good, The Bad & The Rugby, revealing that his son was born at home on the bathroom floor.
"Sunday got even better because a little baby boy arrived at my house," Mike said. "Arrived very quickly. Didn't make it to hospital. On the bathroom floor. So yeah, it was running to the gym, get a mat, get into the bathroom, get the mat on the floor, towels down, brace, brace, brace."
The Queen is "delighted" for her granddaughter
Mike revealed that Zara's friend Dolly, who was also present at the birth of their two daughters, recognised that they wouldn't have time to go to hospital. "Fortunately the midwife who was going to meet us at the hospital wasn't that far away so she drove up just as we had assumed the posit (position) and the second midwife arrived just after the head had arrived," Mike added.
The couple's son, who is their third child together, was born on Sunday 21 March, weighing 8lbs 4oz. His full name is Lucas Philip Tindall – with Philip in honour of both Mike's father as well as Zara's grandfather, Prince Philip.
A spokeswoman for the couple also confirmed: "Zara and Mike Tindall are happy to announce the birth of their third child, Lucas Philip Tindall."
Mike and Zara also have two daughters
The couple are also the proud parents to daughters Mia, seven, and Lena, two. Lucas is now 22nd in line to the throne and will be known as Master Tindall, and not have an HRH title.
His birth comes just a few weeks after Zara's cousin Princess Eugenie welcomed her son August with husband Jack Brooksbank on 9 February. Eugenie and Jack also chose to have Philip as a middle name for their baby boy, in tribute to the Duke of Edinburgh.
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