Tributes have been paid to the Sultan of Brunei's son Prince Azim who has died aged just 38.

The so-called "Playboy Prince" had been suffering from a "serious illness" and was being treated in hospital in the capital Bandar Seri Begawan, state media has announced.

He partied with celebs including Scarlett Johansson, Pamela Anderson and Michael Jackson, and even struck up an unlikely friendship with reality TV star Jade Goody in 2007.

The Sultan's sixth child and fourth in line to the throne died at around 10am on Saturday.

His cause of death has not been made clear, but unconfirmed reports suggested he had been suffering from cancer.

Mariah Carey and Prince Azim
Known as the 'Playboy Prince', he hung out with celebs including Mariah Carey

His estimated wealth was an astonishing $5 billion at the time of his death, according to Media, Entertainment and Arts Worldwide.

Known as a member of the international jet-set, he was often pictured with a number of celebs at lavish parties in Europe and the US.

Michael Jackson, Pamela Anderson and Joan Collins were all photographed alongside the prince over the years, including at his 30th birthday bash.

Other celeb pals included Mischa Barton and Scarlett Johansson.

Prince Azim and Leona Lewis
Prince Azim pictured with Leona Lewis in 2011

He formed a friendship with the late reality TV star Jade Goody, who once described him as a "brilliant mate" after he watched her on Celebrity Big Brother.

They were pictured partying together in 2007, with Jade saying at the time: "He wanted to meet me, we met and got on like a house on fire."

Prince Azim gifted Jade a ring as a "token of friendship" which she claimed was worth around £3 million, although experts later valued it at around £30,000.

In keeping with Islamic tradition, his funeral was held the same day before a week of national mourning was declared, during which time celebrations are banned.

Prince Azim and Dame Joan Collins
Dame Joan Collins was also a pal

Azim also hosted parties attended by gay and transgender rights advocates, including Caitlyn Jenner, Mariah Carey, and openly gay skier Gus Kenworthy.

His open support for the LGBT community in the deeply conservative sultanate of Brunei led to rumours he was also gay, but he never openly discussed his sexuality.

He never married and had no children.

Prince Azim
He is rumoured to have been suffering from cancer

Last year, his father Hassanal Bolkiah announced a new law which could have seen gay people stoned to death.

The rule outlawed gay sex, which had to be independently witnessed in order to secure a conviction.

But following an international outcry, the sultan ruled that a moratorium on the death penalty in Brunei should be extended to the new law.

Azim studied at the International School Brunei, before going on to the prestigious Raffles Institution in Singapore before going to Oxford Brookes University in the UK.

He was known at home as a filmmaker, designer and philanthropist who raised money for terminally ill children and those with autism.