The Queen has said she is dedicating herself "anew to your service", as she marks the 60th anniversary of her accession to the throne, according to BBC.
In a message, she also said she felt "deeply moved" by the support shown for her Diamond Jubilee.
It will be marked by several events, with the main celebrations in June.
The Queen, 85, usually spends Accession Day - the day her father, George VI, died in 1952 - privately but this year has two engagements in Norfolk.
This year`s anniversary will be marked by visits to King`s Lynn Town Hall and the nearby Dersingham Infant and Nursery School.
Crowds are expected to gather to greet the Queen, despite the cold weather.
Two official photographs were released, and a 41-gun salute will be held in Hyde Park, London, followed by a 62-gun salute at the Tower of London.
During her reign, Queen Elizabeth II has seen 11 UK prime ministers come and go, with David Cameron her 12th.
Mr Cameron praised the "magnificent service" given by the Queen and called her a "source of wisdom and continuity".
"With experience, dignity and quiet authority she has guided and united our nation and the Commonwealth over six varied decades," he said.
One former Prime Minister, John Major, reflected on the counsel of the Queen and the many private meetings he had with her during his premiership during an interview on BBC One`s Andrew Marr Show on Sunday.
He said: "Most of the present cabinet weren`t born when the Queen became monarch. So there`s very little she hasn`t seen, very little she doesn`t understand. And anyone who doesn`t listen to her view and consult her when necessary is missing a huge opportunity."
Meanwhile, Sir John has formally launched the Queen Elizabeth Diamond Jubilee Trust to help those in need across the Commonwealth.
He will chair the grant-making body, which will focus on areas such as fighting curable diseases and the promotion of education and culture.
A set of six 1st class definitive stamps, all of which feature official portraits of the Queen, are also being issued to mark the monarch`s milestone.
Moya Greene, Royal Mail`s chief executive, said: "The Queen`s image is one of the most recognisable in the world and we are delighted to bring these iconic images together to mark the 60th anniversary of the Queen`s accession."
The Diamond Jubilee Miniature Sheet marks the first occasion on which official images of the monarch, sourced from stamps, coins and banknotes, have been brought together for a stamp issue.
The Queen`s 60 years as monarch are set to be marked by a series of regional, national and international events during 2012, culminating in a four-day long UK Bank Holiday weekend in June.
Events planned to take place during the summer include the Queen leading a flotilla of a thousand boats along the Thames and a chain of beacons being lit across the country.
The Queen and the Duke of Edinburgh also intend to travel as widely as possible across the UK.
Other members of the Royal Family will visit the 15 other countries where the Queen is head of state, as well as some other Commonwealth countries.
In her message to mark the anniversary, the Queen said: "I am writing to thank you for the wonderful support and encouragement that you have given to me and Prince Philip over these years and to tell you how deeply moved we have been to receive so many kind messages about the Diamond Jubilee.
"In this special year, as I dedicate myself anew to your service, I hope we will all be reminded of the power of togetherness and the convening strength of family, friendship and good neighbourliness, examples of which I have been fortunate to see throughout my reign and which my family and I look forward to seeing in many forms as we travel throughout the United Kingdom and the wider Commonwealth."