The Queen is now the world's oldest monarch following the death of King Abdullah of Saudi Arabia, who passed away aged 90. Her Majesty is one of eight octogenarian monarchs in the world alongside the King of Thailand and the Emperor of Japan.
King Abdullah passed away after a short illness on Thursday. A statement released by the Royal Court early on Friday confirmed that his 79-year-old half-brother, Crown Prince Salman, had now become king.
The late monarch was buried in a ceremony at Riyadh, Saudi Arabia on Friday afternoon. Prince Charles is travelling to Saudi Arabia to pay his respects, Clarence House has confirmed.
The Prince of Wales counted the late royal as a personal friend, and will join other dignitaries honouring King Abdullah. As a non-Muslim, he was unable to attend the funeral service itself, but is understood to be going to a reception instead.
In a statement, Clarence House said, "The Prince of Wales, representing Her Majesty The Queen, will travel to Saudi Arabia to pay his condolences following the death of the Custodian of the Two Holy Mosques, HM King Abdullah bin Abdulaziz Al Saud."
The Queen is also set to become the longest reigning monarch in British history this year. The 88-year-old will exceed her great-grandmother Queen Victoria's reign of 63 years and 216 days in September.
The world's longest-reigning current monarch is Thailand's king Bhumibol Adulyadej, who will celebrate 69 years on the throne in June. The 86-year-old was just 18 when he became king.