A fresh addition to the annals of "lies that Hollywood publicists tell on behalf of the rich and famous" was recently made by one Jason Weinberg, an influential Los Angeles talent rep whose roster of clients includes such high-profile stars as Madonna, Demi Moore and Lindsay Lohan.

On 26 September, Weinberg received an awkward inquiry from the Human Rights Foundation. Was it true, they asked, that another of his clients, Hilary Swank, had accepted a large appearance fee to attend the 35th birthday party of Ramzan Kadyrov, the Kremlin-backed despot in charge of Chechnya?

Absolutely not, he replied, in a dismissive email which suggested it was impertinent to even wonder if an Oscar-winning Hollywood liberal of Ms Swank's stature would consider such a vulgar and unethical career opportunity. "Hilary has no current plans to attend the party," it read.

Fast forward exactly nine days, and, well, I think you can guess what happened. Dressed to the nines, and watched by this newspaper's Moscow correspondent, Ms Swank sauntered up Mr Kadyrov's red carpet, before delivering a charming speech about how much she had already enjoyed her stay in Grozny. "I could feel the spirit of the people, and I could see that everyone was so happy," she said. "Happy birthday, Mr President!"

Joining her was another vintage star: Jean-Claude Van Damme. Although he blotted his copybook by referring repeatedly to "the country of Chechena" [sic] he got warm applause for finishing his speech with the pronouncement: "I love you Mr Kadyrov!" Then, after hundreds of thousands of dollars-worth of fireworks had been fired into the night sky (while Kadyrov shouted "Allahu Akbar" three times), the British violinist Vanessa Mae, performed a brief set. She was paid a rumoured $500,000 (£324,000).

Every good party is followed by a hangover, however. And for all three celebrity guests, that arrived yesterday – courtesy of a statement from the Human Rights Foundation, which had read The Independent's coverage of the event and is calling for their appearance fees to be reimbursed. "Ramzan Kadyrov is linked to a litany of horrific human rights abuses," it read. "It's inappropriate for stars to get paid to party with him. It bolsters his image and legitimises a brutal leader."

So far, neither Swank, nor Van Damme, nor Mae, have tried to answer that pertinent question. Their representatives are apparently hoping that if they say silent, the whole awkward affair will disappear. Either way, the rumbling controversy represents the latest in a string of PR disasters which suggest that a golden era of celebrity endorsement may be slowly coming to a close.

For decades, the international A-list have been able to add to their wealth by agreeing to attend (or perform at) social occasions to which they have no obvious connection. But traditionally, their more shameless exploits in this field have remained happily below the radar. The onward march of technology puts paid to that, though.

Cell phone camera footage of Beyonce, 50 Cent, and Mariah Carey performing at parties hosted by the Gaddafi family caused an almighty row earlier this year. With headline movie salaries already well down, and continuing to fall from their historic high in the mid 2000s, the likes of Van Damme and Swank may face tough decisions about how to finance their Hollywood lifestyles.

Do they abandon the lucrative world of celebrity appearances altogether? Do they ask managers like Weinberg to vet incoming bookings more thoroughly? Or do they just behave like former England cricket captain Mike Gatting, who in 1990 realised the pointlessness of trying to hide dubious efforts to make money overseas, and instead chose to revel in his shamelessness. "I don't know much about how apartheid works," he announced, after agreeing to a tour of South Africa. "But one way to find out is by going there."

Guilty by association? When fame meets infamy

Sting

The singer was criticised for playing a concert in Uzbekistan, organised by the daughter of dictator Islam Karimov. Sting said he was aware of the president's "appalling reputation" but still decided to play. Cultural boycotts were counter-productive, he said.

George Galloway

George Galloway visited Saddam Hussein in Baghdad before the 2003 war as a prominent opponent of sanctions imposed on the regime. Mr Galloway launched an appeal in 1998 to raise money for Iraqis affected by sanctions. In a feisty appearance before a Senate committee, he denied that the appeal had received money through an Iraqi oil company.

Sharon Stone

An inexplicable standing ovation followed Vladimir Putin's slow-tempo, and excruciating, rendition of "Blueberry Hill" at a charity event in Russia. Chief cheerleader: the actress Sharon Stone, with Kevin Costner and Gerard Depardieu adding to the celeb count. Hospitals expecting to benefit from the gala later said they received nothing.

Hilary Swank

Human rights organisations slated the Oscar-winner for attending lavish celebrations in the Chechen capital in honour of President Ramzan Kadyrov. "Happy birthday, Mr President," said Swank, who was joined in Grozny by Jean-Claude Van Damme and the violinist Vanessa Mae. They were all reportedly paid handsomely for their attendance.

Beyoncé