THE man dubbed the world’s most elusive billionaire, Aga Khan IV, has died aged 88.

Prince Karim Al-Hussaini, known best as a spiritual leader, passed away surrounded by his family earlier today – as tributes continue pour in for the beloved racing mogul.

The Aga Khan Development Network, which works across 30 countries around the world, announced his death online.

They said he passed away peacefully in Lisbon on February, 4.

The company left a tribute saying: “Leaders and staff of the Aga Khan Development Network offer our condolences to the family of His Highness and to the Ismaili community worldwide.

“As we honour the legacy of our founder, Prince Karim Aga Khan, we continue to work with our partners to improve the quality of life for individuals and communities across the world, as he wished, irrespective of their religious affiliations or origins.”

The Aga Khan was born in Switzerland but spent most of the last part of his life in France.

He spent most of his life out of the limelight despite being the spiritual leader to around 12 million people from the Ismaili sect of Islam. 

Some of his followers believed he was a direct descendent of the Prophet Mohammed through his daughter, Hazrat Bibi Fatima, and the Prophet’s cousin and son-in-law, Hazrat Ali.

He inherited the title of the 49th Imam of the Shia Imami Ismailis in 1957 when he was just a 20-year-old student at Harvard.

His eldest, Prince Rahim, 53, is expected to be announced as his official successor in the coming days.

Rahim came from his dad’s first marriage in 1969 to British model Sally Croker-Poole.

They had another son and a daughter together before separating from Croker-Poole after 25 years.

He went on to marry Princess Gabrielle in 1998 and the couple had a son but divorced after just six years.

He is also survived by four grandchildren.

At the time of his death he was believed to have been worth over £11 billion.

Along with a sprawling property empire he was also the proud owner of a £200million superyacht and the biggest private jet on the planet.

His prize vessel was a stunning 174ft palace on the seas named The Alamshar after one of his horses.

A Bombardier Global 7500 – which claims to be the world’s biggest private jet – was also apart of his collection.

The plane reached speeds of 710mph and was a whopping 111ft long.

Other big purchases came from his love of racing.

The Aga Khan was the owner of one of horse racing’s most famous ever animals in Shergar who won the Epsom Derby, Irish Derby and the King George.

Khan also owned racehorses Zarkava and Sinndar with the trio making him one of the world’s most successful racing magnates.

Despite some luxury purchase, his vast wealth was mainly used for philanthropic purposes.

This generous lifestyle saw the billionaire even brush shoulders with some of Britain’s most notable faces.

He was an old friend with the late Queen Elizabeth II with the monarch even bestowing the title of “His Highness” on the Aga Khan when he became leader of the Ismaili Muslims.

Queen Elizabeth also hosted the Aga Khan and his family at Windsor Castle to celebrate his Diamond Jubilee.

The event marked a celebration between the Ismaili Imamat and the British Monarchy.

In 2004, he was even appointed Knight Commander of the Most Excellent Order of the British Empire.

Former Minister of Foreign Affairs of Canada, John Baird, paid touching tribute to the great man.

He wrote on X: “He was a remarkable leader and truly one of the most impressive individuals I have ever met.

“Undoubtedly, he stood among the most successful leaders of the past century.”