The Queen has praised the "Commonwealth connection" that allows people from different nations to bond and celebrate "diversity", ahead of Commonwealth Day.
On Monday, London will host a gathering of leaders from the 53 member nations, with the Queen's Commonwealth Day message featuring in a service at Westminster Abbey.
In her message, the Queen added that the Commonwealth is an example of how consensus can "help to create a future that is fairer, more secure, more prosperous and sustainable".
As well as Prime Minister Theresa May and senior members of the Royal Family, Meghan Markle will also attend the service - her first official event with the Queen ahead of her marriage to Prince Harry on May 19.
Prince Harry and Ms Markle signalled their commitment to the Commonwealth and its people when they both mentioned the institution - which has the Queen as its head - during an interview to mark their engagement.
The prince said they looked forward to travelling around the Commonwealth, meeting some of the 2.4 billion people from the 53 member states.
In her message which follows the theme of the 2018 Commonwealth Day service - Towards A Common Future - the Queen says: "Through exchanging ideas, and seeing life from other perspectives, we grow in understanding and work more collaboratively towards a common future.
"There is a very special value in the insights we gain through the Commonwealth connection; shared inheritances help us overcome difference so that diversity is a cause for celebration rather than division.
"We shall see this in action at the Commonwealth Heads of Government Meeting which takes place in the United Kingdom next month, bringing together young people, business and civil society from across the Commonwealth.
"These gatherings are themselves fine examples of how consensus and commitment can help to create a future that is fairer, more secure, more prosperous and sustainable."
Monday's service will be attended by world leaders, high commissioners, ambassadors, senior politicians, faith leaders and more than 800 schoolchildren and young people.
The Commonwealth Games also featured in the message and the Queen highlighted the vital work of the event's helpers, saying: "Voluntary effort, by people working as individuals, in groups or through larger associations, is so often what shapes theCommonwealth and all our communities.
"By pledging to serve the common good in new ways, we can ensure that theCommonwealth continues to grow in scope and stature, to have an even greater impact on people's lives, today, and for future generations."
Organised by the Royal Commonwealth Society, the Commonwealth service is the largest annual inter-faith gathering in the UK.
Former One Direction band member Liam Payne will perform during the Abbey service and the reflection will give by Dr Andrew Bastawrous, an eye surgeon who has turned a smartphone into an examination tool to combat avoidable blindness in developing counties.
Following the service, the Duke and Duchess of Cambridge, Prince Harry and Ms Markle will attend a private reception for people involved in the event.
The Queen's Commonwealth Day Message in full: