William's cousin Zara Phillips, 29, is now engaged too, after her boyfriend, England rugby player Mike Tindall, popped the question at their home in Gloucestershire on Monday.
"I am delighted that Zara has agreed to marry me," Tindall said in a statement. "We are both very excited about the next stage of our lives together."
Added Phillips: "I was really shocked when Mike proposed but I am very happy."
There is no news on a wedding date or whether the blonde showjumper – who, as the daughter of William's aunt, Princess Anne, is 12th in line to the throne – will beat William and Kate to the altar in late April.
A Buckingham Palace spokeswoman tells PEOPLE that Phillips and Tindall, 32, excitedly informed their families of the news shortly after she accepted his proposal.
The ring is described as a single solitaire diamond with pavé set diamonds on a split shank, set on a platinum band. No designer or store has been revealed for the jewelry.
Buckingham Palace released a short statement on behalf of Phillips's parents on Tuesday morning, which read: "The Princess Royal and Captain Mark Phillips are pleased to announce the engagement of their daughter Zara Phillips to Mr. Mike Tindall, son of Mr. Phillip and Mrs. Linda Tindall."
Zara's grandmother, Queen Elizabeth, and the Duke of Edinburgh are "delighted with the news," a spokeswoman tells PEOPLE.