Queen Camilla pulled out of the service at the last minute due to illness, as she recovers from acute sinusitis ahead of the US state visit later this week.

As a result, the monarch arrived with his private secretary Sir Clive Alderton by his side instead.

But, the arrival that captured perhaps the most surprise was His Majesty’s younger brother, Prince Andrew.

The Duke of York – who is rarely seen at public royal gatherings anymore following his fall from grace over accusations of sexual assault by the late Virginia Giuffre, which he denies and his friendship with convicted child sex offender – arrived with his former wife Sarah Ferguson.

The Duchess of York walked into the cathedral beside her ex-husband and they both spoke with the clergy as they made their way to their seats.

Prince Andrew’s sister, Princess Anne and her husband Vice Admiral Sir Timothy Laurence were also in attendance, as were the Duke and Duchess of Gloucester.

Also joining in the private family event was Sophie, Duchess of Edinburgh along with the Prince and Princess of Wales.

They all arrived shortly before King Charles and widow the Duke of Kent.

Prince Edward, the 89-year-old Duke of Kent is Queen Elizabeth II’s first cousin and married to Katharine, Duchess of Kent in 1961.

They had three children together – Lady Helen Taylor, Lord Nicholas Windsor and George Windsor, the Earl of St Andrews.

After marrying, the duchess was a senior working member of the British royal family for decades but stepped back from royal life to teach music at a local school in Hull, in north-east England.

The duchess, who preferred to be known as Mrs Kent, was a pianist, organist and singer.

She went on to found the charity Future Talent to break down barriers for young musicians and provide them with instruments.

But in recent decades she had kept a low profile, retiring her royal title in 2002.

The couple lived at Kensington Palace, which is where she died on September 4, surrounded by her family.

While the royal family is famously Protestant, the duchess converted to Catholicism in 1994, making her Requiem Mass a historic one.

As a result, Pope Leo XIV sent a message to King Charles and the Duchess’ family, which was read out during the service by Archbishop Miguel Maury Buendia, Apostolic Nuncio to Great Britain.

“I was saddened to learn of the death of Her Royal Highness The Duchess of Kent, and I send heartfelt condolences, together with the assurance of my prayerful closeness, to Your Majesty, the Members of the Royal Family, and especially to her husband, The Duke of Kent, and their children and grandchildren at this time of sorrow,” the pontiff wrote.

“Entrusting her noble soul to the mercy of our Heavenly Father, I readily associate myself with all those offering thanksgiving to Almighty God for The Duchess’s legacy of Christian goodness, seen in her many years of dedication to official duties, patronage of charities, and devoted care for vulnerable people in society.

“To all who mourn her loss, in the sure hope of the Resurrection, I willingly impart my apostolic blessing as a pledge of consolation and peace in the Risen Lord.”

It also marked the first time since Westminster Cathedral was built in 1903 that it’s been used for a royal funeral.

Members of the royal family stood outside the church as the wicker coffin, draped in a royal flag, was placed into the back of a hearse bound for Windsor.

Her Royal Highness will be laid to rest at the Royal Burial Ground at Frogmore.