The Queen's granddaughter Zara Tindall is expecting a baby with her husband Mike Tindall.
Princess Anne's daughter, who married the former England rugby union
international in a private ceremony in July 2011, will give birth in the
New Year.The birth will follow the keenly anticipated arrival of the Duke and Duchess of Cambridge's baby, which is expected in the coming days.
However, because Zara Tindall does not hold a royal title, her baby will not be called his or her 'royal highness'.
An official statement said: "Mr and Mrs Mike Tindall are very pleased to announce that Zara Tindall is expecting a baby in the New Year.
"The Princess Royal and Captain Mark Phillips, Mr Phillip and Mrs Linda Tindall, and members of both families are delighted with the news.
"This baby will be the first child for Mike and Zara and the third grandchild for The Princess Royal."
Zara, 32, is an accomplished sportswoman and last year won an Olympic silver medal as part of the equestrian eventing team.
She competed at the weekend at the Barbury International Horse Trials, said Sky News' Royal Correspondent Paul Harrison.
The child will be Princess Anne's third grandchild, as her son, Peter Phillips, has two daughters.
Zara Tindall, who is currently 14th in line to the throne, met her husband at the 2003 rugby World Cup in Australia.
The couple married in Edinburgh two years ago in a ceremony attended by all the senior royals.
But, just months later, the rugby player was fined and booted out of the 2011 World Cup squad over a team night out.
He apparently took part in a "dwarf tossing" competition with fellow players and was seen embracing an ex-girlfriend.
Tindall's fine was eventually reduced and his suspension set aside after an appeal found he did not intentionally mislead the team's management.
Zara and Mike Tindall currently live on Princess Anne's Gatcombe Park estate in Gloucestershire.