The Princess Royal had a special occasion to mark on Monday as her eldest son, Peter Phillips, turned 44.
Peter is the Queen's eldest grandchild and was born to Princess Anne and her first husband, Captain Mark Phillips, on 15 November 1977. He is also the older brother of Zara Tindall.
Having attended the University of Exeter, he graduated with a degree in sports science in 2000. Peter has worked for Jaguar as a corporate hospitality manager and then for the Williams racing team.
READ: Princess Anne commands attention in military uniform on Remembrance Sunday
WATCH: Royals sing God Save The Queen on Remembrance Sunday
He also had a role as a manager for RBS, before leaving in 2012 to become a managing director at sports and entertainment agency, SEL UK.
In 2003, he met Canadian management consultant Autumn Kelly, and the couple began dating. Their engagement was announced on 28 July 2007.
Peter and Autumn finalised their divorce in June
The pair were married at St George's Chapel in Windsor on 17 May 2008, and they welcomed their first child, Savannah, in December 2010, followed by Isla two years later.
Sadly, Peter and Autumn's marriage wasn't to last and they separated in 2019, finalising their divorce in June 2021.
In a statement, the former couple confirmed that they would continue to live on their Gloucestershire estate in order to bring up their daughters.
MORE: Why Princess Anne's first wedding had a special nod to Prince Charles
MORE: 11 royal marriages that ended in divorce
Baby Peter pictured in 1977 with Princess Anne and the Queen
Peter, who is currently 18th in the line of succession, does not have a courtesy title and he does not carry out royal duties.
In the 2020 ITV documentary Anne: The Princess Royal at 70, Peter explained: "We were always brought up on the understanding that we were going to have to work. We were going to have to go out and earn, earn our living. Regardless of the fact of who our grandmother or who our mother was."
Peter's birthday comes the day after Anne's elder brother, the Prince of Wales, celebrated turning 73.
Princess Anne was among the senior royals to attend the Festival of Remembrance at London's Royal Albert Hall, as well as the Remembrance Sunday service, where she laid a wreath at the Cenotaph.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.