The Princess Royal, 71, was part of the wedding party watching her ex-husband, Captain Mark Philips, give away his daughter Stephanie during the ceremony. The 24-year-old, who is the daughter of Captain Phillips and his second wife, has maintained a close relationship with her half-siblings, Zara Tindall and Peter Phillips.
Both were attended along with their partners, Mike Tindall and Lindsay Wallace.
Stephanie’s mother, Sandy Pflueger, was married from 1997 to 2012 to Captain Phillips after his divorce from Princess Anne.
But after Princess Anne and Captain Phillips divorced in 1992, Princess Royal’s ex-husband continued to live on her Gatcombe estate.
Stephanie also lived on the Gloucestershire grounds and grew up on Aston Farm.
Stephanie’s wedding to William Hosier took place in Gloucestershire, Tetbury, near St Mary’s The Virgin Church.
The queen’s granddaughter, Zara, was a vision in blue, which she fitted with a striking hat and nude shoes.
She watched as her two eldest children, eight-year-olds Mia and Lena, four, played the role of bridesmaids.
But as the young sisters arrive on their way to the service, Princess Anne seems to frown at Lena, who looks grumpily at the ground.
READ MORE: New Archie photos show ‘significant’ difference with Cambridges
She shares a love for horses found in many members of the royal family, as well as being passed down from her mother, herself an Olympic rider.
Sandy competed for the USA at the Los Angeles Olympics, originally from Hawaii.
She shares this coveted achievement with Zara, who represented Team GB at the 2012 London Olympics.
Stephanie, who has not enjoyed the same level of success in the sport, recently graduated from the University of Worcester.
She studied Business Management after attending Dean Close School in Cheltenham.