The Queen turns 91 today - her "real" birthday, as the monarch traditionally has two.
The royal is thought to be at Windsor Castle, where she traditionally spends a month-long residence, known as Easter Court.
Her "official" birthday - marked by the Trooping the Colour ceremony - takes place in the summer.
- Guardsmen play 'Happy Birthday' for Her Majesty:
Today's more low-key anniversary may suit the monarch, who is said to prefer practical gifts to overly extravagant ones.
A washing-up apron and a casserole dish given to her by family members are among her most treasured gifts.
- So what are some of the Queen's favourite gifts?
Peggy the Shetland pony
Princess Elizabeth's first horse was a gift from her grandfather, King George V, when she was four years old.
A lifelong passion for horses and riding followed.
Susan the Corgi
An 18-year-old Elizabeth was thrilled to be given her first Pembroke Welsh corgi by her parents.
Beloved by the Queen, Susan was apparently known to nip at servants' legs and once bit a royal clockwinder on the ankle.
Big Mouth Billy Bass
A mounted fish which moves and mimes the words to 'Take Me To The River' or 'Don't Worry, Be Happy'.
The Queen was apparently introduced to item by the Princess Royal and one stands on top of the grand piano in Balmoral.
She was also given a Rocky Lobster, a lifesize singing crustacean which performs 'Do Wah Diddy Diddy' and 'Rock The Boat'.
The Queen is said to sing along to the tunes.
Prince Harry delighted his grandmother with the gift on her 90th birthday.
Harry arranged to perform a short cabaret with ventriloquist Nina Conti at the Queen's party and had the Royal Family in fits of laughter as he acted as Conti's dummy.
On her wedding day the Queen's father, George VI, gave her a glittering necklace, dating from 1850.
It was made of 16 large oblong sapphires surrounded with round diamonds, with a pair of matching sapphire and diamond drop earrings.
The Queen has added a tiara and bracelet to the collection, and has worn the jewels many times.