King Charles III will hail the value of traditional alliances and international friendships at a time of "increasing pressures of conflict" in his Commonwealth Day message.
The annual celebration of the Commonwealth, to be marked on Monday with a service at Westminster Abbey, will see the biggest gathering of senior royals since the arrest of his brother Andrew Mountbatten-Windsor.
There will also be contributions at the service from performers including former Spice Girl Geri Halliwell-Horner and Strictly Come Dancing's Oti Mabuse.
Against a backdrop of war in the Middle East and Ukraine, the King will commend the unifying force of the Commonwealth, a voluntary association of 56 countries.
"It is often in such testing moments that the enduring spirit of the Commonwealth is most clearly revealed," the King's message will say.
