Prince George and Princess Charlotte Make Surprise Appearance at Prince Philip's Memorial Service

Kate Middleton and Prince William's oldest children are paying tribute to their late great-grandfather.

Prince George, 8, and Princess Charlotte, 6, made a surprise appearance at Prince Philip's memorial service on Tuesday.

The siblings — who are on their Easter break from school — arrived at Westminster Abbey with their parents shortly before the start of the service.

While Kate and William's youngest child, Prince Louis, 3, was deemed too young to attend the service, George and Charlotte were joined by their cousins — Savannah and Isla Phillips, the children of Peter Phillips, and Mia Tindall, who accompanied her parents Zara and Mike Tindall.

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The royal couple ushered George and Charlotte to greet the clergy as they entered the Abbey. When Charlotte met the Archbishop of Canterbury, Justin Welby, he bent down to talk to her face-to-face and she gave him a big smile. As they reached the end of the welcoming line, Charlotte held her hand out for her mom Kate.

Tuesday's service also marks the first public outing for William and Kate since they returned from their royal tour of the Caribbean on Sunday.

Tim Rooke/Shutterstock Prince George and Prince William

The poignant ceremony will provide an opportunity for representatives of the many charities and organizations that Prince Philip worked with to pay tribute to him. Prince Philip's funeral last April was scaled down due to COVID-19 government restrictions at the time.

In a surprise move, Queen Elizabeth was escorted by her son Prince Andrew to the service. The outing marks Andrew's first public event since he settled a sexual assault lawsuit with his accuser Virginia Giuffre six weeks ago. His daughters, Princess Beatrice and Princess Eugenie, and their husbands, Eduardo Mapelli Mozzi and Jack Brooksbank, were also in attendance.

Samir Hussein/WireImage Princess Charlotte and Kate Middleton

The royal couple returned home from their eight-day Caribbean tour on Sunday morning. Last week, William and Kate traveled to Belize, Jamaica and The Bahamas.

Just hours before their flight home, William released an unprecedented statement about the controversy that has followed the couple on their tour.

RELATED: The Biggest Moments from Kate Middleton and Prince William's Controversial Caribbean Tour

PA Images / Alamy Stock Photo

For the first time, the royal couple faced significant backlash on an official tour. Although they have received warm welcomes from many locals, they are also encountering mounting tensions in the Caribbean nations where William's grandmother, Queen Elizabeth, remains head of state.

William reflected on the future governance of the Caribbean nations in his statement on Saturday, saying, "I know that this tour has brought into even sharper focus questions about the past and the future. In Belize, Jamaica and The Bahamas, that future is for the people to decide upon."

RICHARD POHLE/POOL/AFP via Getty Images Princess Charlotte and Kate Middleton

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Samir Hussein/WireImage Prince George and Princess Charlotte

The rising tide of social and economic justice movements — including calls for slavery reparations and indigenous rights expansion — are rapidly reshaping contemporary views of the monarchy at a time when it is in transition: As Elizabeth, 95, marks 70 years on the throne, William and Kate are increasingly the modern face of both the family and the institution.

"The future of the British monarchy is more about William and Kate—spiritually, not in terms of actual succession," historian Sarah Gristwood tells PEOPLE.