How do you get these stars to come to your 26th birthday party?

(It's easy if your dad's a Sultan)

With promotional budgets squeezed and once bonus-rich bankers keeping a low profile, the celebrity junket, in which A-listers are whisked off in private jets to entertain guests at chandeliered private dinners, has become an all-too-irregular occurrence.

As fewer billionaire admirers are willing to pay up to £500,000 for an evening's entertainment, the world's more reluctant pop stars have had to go back to good old-fashioned touring to top up their coffers. So the latest bash thrown by Prince Azim, the party-loving son of the Sultan of Brunei, will have been a moment of profligate light relief for celebrities from a more prudent era.

The prince's birthday parties have become something of a fixture on the celebrity party scene and this year's bash to toast his 26th, and the recent graduations of his nearest siblings, spared little expense.

Azim invited a constellation of silver-screen goddesses and pop-stars to his bash, held in the luxury surroundings of Stapleford Park country house, a five-star hotel owned by the prince's mother, Mariam Aziz. Hollywood greats such as Faye Dunaway, Sofia Loren and Joan Collins rubbed shoulders with Janet Jackson, Mariah Carey and Chaka Khan – who later performed a set for the guests. For the younger generation, current Hollywood heart throbs Adam Gregory, Sean Faris and Robert Buckley attended.

So extravagant was the party for the prince and his three siblings – Prince Mateen, Princess Azemah and Princess Fadzillah – that the Nottinghamshire florist who filled the hotel with white roses said the bill for flowers alone came to £70,000. (A spokesperson for the Prince later dismissed this figure as "crazy".)

Jeff Allen, a music producer who has known them since the 1980s, insisted that the family, one of the richest dynasties in the world, are actually keeping a lid on expenses. "If anything, throwing a party at Stapleford Park is actually cheaper because his mum owns the hotel," he said.

"They threw a party because they all happened to be in London at the same time and had various graduations and birthdays to celebrate."

The bash was a throwback to a recent past when celebrities regularly mingled with wealthy patrons. Acts such as the Rolling Stones and Eric Clapton often found themselves flown out by hedge-fund managers to add rock sparkle to a corporate bash. Thanks to the credit crunch, it is now largely wealthy foreign rulers and oligarchs who keep the "celebrity hire" industry going.

Prince Azim, whose personal fortune has been estimated at £13.5m, has cemented a reputation as the latest Brunei royal with a penchant for partying. Earlier this year, the prince reportedly hired an entire VIP area of the exclusive Mahiki nightclub in Mayfair – for which he was billed an estimated £150,000 – in order to throw a party for the Pussycat Dolls. The guest lists for his annual functions at Stapleford Park read like a Who's Who of Hollywood glamour. Last year, Michael Jackson, then a friend of the family, and Naomi Campbell came.

The prince, who recently dropped out of officer training at Sandhurst and hopes to pursue a career in film producing (he is seen as the most artistic family member), has said that he realised his good fortune. "I'm grateful to have what I have," he said, "and I like to share it."