Sunday’s Oscars will be notable for many things, including the possible triumph of a silent movie and the return of Billy Crystal as host after Eddie Murphy’s flameout. But most notable, of course, will be the gowns. This year fashion brands have been poised to fight over new hopefuls Jessica Chastain, Michelle Williams, Rooney Mara, Emma Stone and Bérénice Bejo, along with the usual slew of A-list talents. But how each of them decides on their frocks, jewels and accessories – or what they might be paid to do so – remains secret.

“There’s a hugely evolved culture of paying to wear clothes and product. Some actresses sign four-event contracts to wear designers, with giant perks and huge money,” says a Hollywood insider. “Everyone has a stake: the agents, the stylists, they all profit from the relationship.”

“But stars will not talk about the money,” says Simon Astaire, a former broker of celebrity-brand ambassadorships (notably between Bulgari and actress Charlize Theron, and Armani and Lady Helen Taylor). “They don’t want to be seen to be paid.”