The Queen has urged the people of the Commonwealth to "support those in need" and others who "feel excluded" in her annual message to the family of nations.
In her message to mark Commonwealth Day the Queen said helping those less fortunate would be a way of embodying this year's Commonwealth theme of inclusivity.
The Queen's message will form part of the annual Commonwealth Day service at Westminster Abbey being held this afternoon and attended by the Duke of Edinburgh, the Duke and Duchess of Cambridge, Prince Harry and a host of dignitaries.
In the event's programme, the Queen, who is head of the Commonwealth, wrote: "Today, and in the year ahead, the theme An Inclusive Commonwealth is an inspiration for us all.
"Let us give it practical effect by supporting those in need and those who feel excluded in all walks of life. By doing so, we will continue to build a truly representative Commonwealth community."
The Commonwealth has 53 member countries representing 2.3 billion people, of which 60% are under 30.
The Queen also said working together for the common good was an essential ingredient of belonging to the family of nations.
The monarch wrote: "Each of us has cause to celebrate the sense of belonging expressed in our 2016 theme: An Inclusive Commonwealth.
"Our recognition of this value, and the wisdom of mutual respect for each other, is set out in the Commonwealth Charter. Its opening words, 'We the people of the Commonwealth' convey the conviction that individuals, as well as governments, build and shape our success.
"Being inclusive and accepting diversity goes far deeper than accepting differences at face value and being tolerant.
"True celebration of the dignity of each person, and the value of their uniqueness and contribution, involves reaching out, recognising and embracing their individual identity."
Kamalesh Sharma, the Commonwealth's out-going Secretary General who will be succeeded by Baroness Scotland in a few weeks, said in his message: "Taking strength from its diversity, the Commonwealth succeeds in creating common ground on which to stand together in answering the challenges of our times.
"Mutual support, with respect and understanding for the dignity and contribution of all, gives potency to the acclaimed convening power of the Commonwealth. The Charter of the Commonwealth now embodies our high and shared purpose.
"Globalisation, the digital revolution and interdependence make us both a rapidly compacting but also colliding world. The strengths of the Commonwealth were never needed more to assert fairness in global outcomes and trust in the richness of our human identities."
The Westminster Abbey service will be the largest annual inter-faith gathering in the UK. Highlights will include the principal reflection given by Kofi Annan, former secretary general of the United Nations, and a musical performance by Ellie Goulding.
Guests of honour among the 2,000 strong congregation will include Mr Sharma, the prime minister of Malta, Joseph Muscat, alongside High Commissioners, Commonwealth dignitaries, religious Leaders and more than 1,000 school children.
The Queen and members of the Royal Family will meet people involved in the service, and after the event William, Kate and Harry will attend a reception for members of the congregation.
This evening the Queen and Philip will be Mr Sharma's guest, at the annual reception which traditionally takes place on Commonwealth Day - celebrated today - at Marlborough House, the home of the Commonwealth Secretariat.