Blending glamour and a good cause is harder than it looks, but brings in "an awful lot of money", Dame Helen Mirren says.
"It's always a slightly uncomfortable mix," she said on the red carpet at Thursday's French Riviera fundraiser for the amFAR Cinema Against Aids charity.
But it "raises an awful lot of money" for a very important organisation, she noted.
"Aids is still a devastating illness, destroying communities all over the world and this charity will help with that so we'll make Aids history," Oscar-winning star Dame Helen said.
Milla Jovovich, Adrien Brody, Chris Tucker, Kirsten Dunst, Juliette Binoche, Vanessa Paradis, Karolina Kurkova and Juliette Binoche joined Dame Helen at the event, held at the exclusive Hotel du Cap-Eden Roc just outside Cannes, where the international film festival is under way.
"What do I love about amfAR? The fact that they've made sure to save people over the last 20 years - so many people today that are living with HIV/Aids are living because of the research amfAR does," said Milla, a regular at the event.
Adrien, a keen painter as well as an actor, said he was both a guest and a contributor to the evening's auction with one of his works.
"It's a pretty grand piece that I've donated for amfAR this evening, so I'm very excited. I'm very excited to share that," he said.
Australian actor Joel Edgerton was unsure when asked if he planned to bid on any of the auction items.
"The trouble with me is I haven't done the Marvel movies yet, so I can't spend lots of money, but I want to support and I will in my own way," he said. "I have a bit of a twitch, I might end up buying everything."
According to amfAR figures, to date the Cinema Against Aids galas have raised more than 170 million dollars (£116 million) for its research programmes.
Master of ceremonies Kevin Spacey poked fun at US Republican presidential hopeful Donald Trump, saying he would enjoy visiting a place with "so many casinos to bankrupt".
And the American Beauty actor did not stop with the ridicule of billionaire businessman Trump over his Atlantic City, New Jersey, casino history. He then did impressions of former US president Bill Clinton and the late actor Jack Lemmon.