Britain celebrates the Queen's official 90th birthday in style

Elizabeth Alexandra Mary (Elizabeth II) was born on 21 April 1926 in London to the then-Duke and Duchess of York, George VI, and Elizabeth Bowes-Lyon, who later became the King and Queen.

Elizabeth II had undertaken public duties during the World War-II (1939-45) and served in the Auxiliary Territorial Service.

On 6 February 1952, she became the Queen (crowned on 2 June 1953).

At the time of birth, Elizabeth was third in the succession line to the throne after her uncle Edward, Prince of Wales and father, the Duke of York.

In 1936, after her grandfather's death, Edward VIII became King.

However later that year, King Edward abdicated following his proposed marriage to Wallis Simpson, a divorcee.

Elizabeth's father became king, and she became 'heir presumptive'.

In 1952, Elizabeth II ascended the throne following the death of her father, King George VI, when she was only 25 years old.

In 1953, her coronation was watched by an estimated 27 million people on TV and 11 million listened on the radio.

She became the monarch of United Kingdom, Canada, Australia, New Zealand, Union of South Africa, Pakistan and Ceylon (Sri Lanka).

Queen Elizabeth II is the "longest reigning female monarch" in world history.

Also, Queen Elizabeth II and Prince Philip Mountbatten's marriage in 1947 had been the longest royal marriage ever.

Queen Elizabeth II is the oldest living monarch and has two birthdays (one actual, another official).

As the head of state of 16 Commonwealth states, her portrait is on the maximum number of currencies.

Queen Elizabeth II became Britain's longest-ruling monarch as she surpassed the historical record set by Queen Victoria, her great-great-grandmother.

The Queen's reign, which began on 6 February 1952, had extended for 63 years and seven months.

The Queen was on official duties in Scotland on this historic event.

PM Cameron had called the Queen "a symbol of Britain's enduring spirit admired around the world."

Queen Elizabeth II, Britain's longest-serving monarch, is celebrating her 90th birthday today and is expected to greet people in Windsor along with Prince Philip.

She was first greeted by the Royal Mail delivery centre in Windsor, which is marking its 500th anniversary, on the eve of her birthday.

Royal fans, well-wishers, and leaders from across the world wished the Queen on her birthday.

Prince William, the Duke of Cambridge, has paid special tribute to Queen Elizabeth on her 90th birthday for helping him cope with his mother's death in 1997.

He said that the Queen was a very strong female influence when he was young.

He added that he had someone like the Queen to look up to when he lost a loved one.

On the occasion of her official 90th birthday, Britain reigning monarch Queen Elizabeth took the salute at a special Trooping the Colour parade in London (​1,600 soldiers and 300 horses took part in i

She later gathered with the entire Royal family on the balcony of Buckingham Palace to watch a fly-past.

A Patron's Lunch will be held on The Mall outside Buckingham Palace.