The Prince of Wales and the Duchess of Cornwall lit candles in a Ukrainian cathedral on the second day of their royal tour of Canada.
Prince Charles and Camilla were visiting the nation's capital Ottawa and spoke with members of the local Ukrainian community.
They also honoured Canada's war dead.
The royal couple are on a three-day tour of the country - of which the Queen is head of state - as part of a tour to mark the Platinum Jubilee.
The prince and duchess visited the Assumption of the Blessed Virgin Ukrainian Orthodox Cathedral where they observed a service and recited a prayer.
They also listened as a priest told them Ukrainians would "never forget" the support extended to their country by Boris Johnson and the Royal Family - and then met members of Canada's Ukrainian community to learn about local efforts to support their war-torn homeland.
According to Clarence House, Canada is home to 1.4 million people of Ukrainian descent - one of the world's largest Ukrainian populations.
Earlier, the couple visited the National War Memorial to honour Canada's war dead - they stood motionless as a bugler played the last post and a period of silence was observed.
Prince Charles is set to meet people who have been supported by the 30 Birds Foundation, which helped evacuate Afghan schoolgirls and settle them in Canada.
Canada's Prime Minister Justin Trudeau will meet the royal couple at a reception in Rideau Hall, the official residence of the Queen in Canada and her representative the governor general of Canada.
On Tuesday, Prince Charles vowed to listen to and learn from Canada as it starts a process of reconciliation with indigenous communities.