King Charles posed with Ukraine's President Volodymyr Zelensky ahead of their Coalition of the Willing meeting at Windsor Castle.
Photographers captured a striking photo of the two leaders as they took their salute before inspecting a Guard of Honour.
King Charles wore a crisp grey three-piece suit and black leather oxfords, conveying a serious tone through his facial expression.
Earlier in the week, King Charles and Queen Camilla attended an ecumenical service with Pope Leo XIV in the Sistine Chapel at the Vatican.
King Charles is a man on the move.
The royal couple's busy schedule included a moment of public prayer beneath the Michelangelo ceiling, captured by photographers.
Autor's resume: King Charles meets with Ukraine's president.