Zara and Mike Tindall have named their new baby daughter Lena Elizabeth.
The Queen's granddaughter gave birth to her second child, weighing 9lb 3oz, at Stroud Maternity Unit in Gloucestershire on 18 June.
Her husband was present at the birth.
A spokeswoman for the ex-Olympic horse rider and former England rugby union star: "The name is Lena Elizabeth. It was just a name they liked."
The name Elizabeth is in honour of the 92-year-old monarch.
Lena is 19th in line to the throne and the Queen and the Duke of Edinburgh's seventh great-grandchild.
She is the younger sister of four-year-old Mia Tindall, and also a second cousin to Prince George, Princess Charlotte and Prince Louis.
Lena, like her mother, is not an HRH and does not have a royal title.
The birth comes just over a year since Zara, a champion equestrian rider who won a team silver medal in the London 2012 Olympics, suffered a miscarriage.
When Zara - daughter of the Princess Royal - was born in 1981, she had no right to a title, being born down the female line as the child of a daughter of a sovereign.
The Queen's seven great-grandchildren are: Savannah and Isla Phillips; Prince George, Princess Charlotte and Prince Louis of Cambridge; and Mia and Lena Tindall.