Bolkiah and Hakim were married in a private ceremony in Kuala Lumpur, Malaysia in 2005. The union bore two children who joined eight other heirs from previous marriage.
"The Sultan has divorced his wife Azrinaz Mazhar Hakim and all the royal titles that have been awarded to the Sultan's former wife have been withdrawn," Grand chamberlain Haji Alauddin Haji Abu Bakar announced on Radio Television Brunei.
He said the divorce was granted based on "special reasons" but no other details were given. Rumours of the royal break-up had been circulating in the capital in recent weeks.
The ruler of the small oil-rich country remains married to his first wife whose son, Prince Al Muhtadee Billah Bolkiah, is the heir to the throne.
Sultan Bolkiah's second marriage to former stewardess Abdul Aziz ended in divorce in 2003.
Sultan Hassanal Bolkiah was born on July 15, 1946 in Brunei Town (now called Bandar Seri Begawan). He became crown prince in 1961
and sultan on Oct. 5, 1967 after his father abdicated voluntarily. His coronation was held on Aug. 1, 1968. Like his father, he has been knighted by Queen Elizabeth II of the United Kingdom, of which Brunei was a protectorate until 1984.
Bolkiah is known for his collection of expensive cars estimated at more than 3,000 units that include classic and top-of-the-line Rolls Royce, Bentley, Ferrari, Porsche, Mercedes Benz, and other expensive cars.
His official residence is the Istana Nurul Iman which has 1,888 rooms, 290 bathrooms and a floor area of 2,152,782 square feet (200,000 m²). It's the world's second largest palace after Beijing's Forbidden City (720,000 m²).