Prince and Princess Michael of Kent put on a brave face as they attended a memorial for the late King Constantine – just two days after the death of their son-in-law, Thomas Kingston.
The couple were seated on the second row inside St George's Chapel, Windsor Castle, at the thanksgiving service on Tuesday morning.
Just hours later, Buckingham Palace announced the death of their daughter Lady Gabriella Kingston's husband.
Mr Kingston, known as Tom, was found dead at an address in Gloucestershire on Sunday evening, and emergency services were called to the scene shortly after 6pm.
An inquest will be held to establish the cause of death, but there are no suspicious circumstances and no other parties involved.
A statement released on behalf of Lady Gabriella Kingston, Mr Martin and Mrs Jill Kingston, Mrs Joanna Connolly and Mrs Emma Murray, said: "It is with the deepest sorrow that we announce the death of Thomas Kingston, our beloved husband, son and brother.
"Tom was an exceptional man who lit up the lives of all who knew him. His death has come as a great shock to the whole family and we ask you to respect our privacy as we mourn his passing."
Proud father Prince Michael walked his daughter, Lady Gabriella, known as Ella, down the aisle on her wedding day to Thomas on 18 May 2019.
The pair tied the knot at St George's Chapel, Windsor Castle after several years of dating.
Earlier this month, Lady Gabriella and Thomas joined the likes of Queen Camilla at a star-studded night out in London to celebrate the works of Shakespeare.
Lady Gabriella, a godchild of the late King Constantine, did not attend the thanksgiving service on Tuesday. Her brother and his wife, Lord and Lady Frederick Windsor, were also absent.
A Buckingham Palace spokesperson said: "The King and the Queen have been informed of Thomas’s death and join Prince and Princess Michael of Kent and all those who knew him in grieving a much-loved member of the family.
"In particular, Their Majesties send their most heartfelt thoughts and prayers to Gabriella and to all the Kingston family."