No public events are planned and the couple's anniversary celebrations will be a restricted to family members and friends.
Albert II met his future wife, Italian princess Paola Ruffo di Calabria, in 1958 at a Belgian embassy reception in Rome following the inauguration of Pope John XXIII.
Several months later Paola was introduced to the Belgian people. Local media said: "The charm and beauty of the blond princess from the south quickly captured the hearts of the Belgians."
The couple got married on July 2, 1959 in Brussels. Local newspapers wrote that Paola, whose grandmother on her father's side, Laure Mosselman du Chenoy, was Belgian, had "returned to her roots."
The couple has 12 grandchildren from their three children - Prince Philippe born in 1960, Princess Astrid in 1962 and Prince Laurent in 1963.
The royal couple went through a serious crisis seven years later when they started living separately and reportedly had affairs. Media reports said divorce documents had been drawn up.
Later Mario Danneels published a book on the couple, where she stated that Albert had had an affair with Baroness Sybille de Selys-Longchamps. The couple reportedly had a child, Delphine Boel, who was born in 1968.
In an interview on her 70th birthday, Paola said they had difficult period at that time "but now we both say that we were meant for each other. We are very happy now."
In 1993, Albert and Paola became the new royal couple after Albert's older brother King Boudewijn died. The couple is currently considered an ideal family by millions of Belgians.
The Belgian Royal House will also mark the 20th wedding anniversary of Princess Astrid and her husband, Prince Lorenz, on September 22 and the 10th wedding anniversary of Philippe and Mathilde on December 4.
To mark the occasions, the king and queen will hold a reception in the Royal Palace of Laeken on August 30. A total of 68 Belgian couples who also got married on July 2 will be invited.
Five couples who got married on the same day as Princess Astrid and Lorenz and five couples who got married on the same day as Philippe and Mathilde will be also invited.
