Prince Philip has died, aged 99.

Prince Philip, the Duke of Edinburgh, has died at the age of 99.

In a brief statement, the royal family said "It is with deep sorrow that Her Majesty The Queen has announced the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh.

"His Royal Highness passed away peacefully this morning at Windsor Castle."

The family said further announcements will made in due course. No cause of death was shared.

The Queen's husband of 73 years had suffering failing health in recent years and officially retired from royal duties in 2017.

Image: Getty.

In March, he was released from hospital after more than a month, after being admitted as a "precautionary measure".

During his stay, the palace said he was battling an infection. The Duke underwent a procedure for a pre-existing heart condition at a London Hospital on March 4.

Speaking on Friday, British Prime Minister Boris Johnson paid tribute to Prince Philip.

"He helped to steer the Royal Family and the monarchy so that it remains an institution indisputably vital to the balance and happiness of our national life," Johnson told media outside Downing St.

Australian Prime Minister Scott Morrison shared a statement honouring the Duke.

"Australians send our love and deepest condolences to her Majesty and all the Royal family. The Commonwealth family joins together in sorrow and thanksgiving for the loss and life of Prince Philip.

"God bless from all here in Australia."

Prince Philip and the Queen married in 1947 - five years before she became Queen - and had four children together; Prince Charles, Prince Andrew, Princess Anne and Prince Edward.

They also had eight grandchildren and 10 great-grandchildren.

Prince Philip was born on the Greek island of Corfu on 10 June 1921.

He was the longest-serving consort in British history.

Feature image: Getty.