Catherine adores her locks

Catherine Zeta Jones has taken the unofficial Hollywood motto - nothing 'Exceeds Like Excess' - to mouth watering heights with the revelation that she relies on truffles and Beluga caviar shipped in from Iran to keep her famous locks silky smooth.

According to a London daily, the 37-year-old wife of fellow Hollywood star Michael Douglas spends approximately $US470 on liquified sturgeon roe alone per treatment to give her brown hair a lustrous shine. The treatment also involves truffles and eggs, according to the Mail, and the Beluga caviar is flown in from Iran five days ahead of her treatments at Hari's, a celebrity hair salon, in South Kensington, England.

"Catherine discovered the caviar treatment last summer and was astounded by the difference it made to her hair," an anonymous source told the tabloid.

"She has an incredibly rich and vibrant natural hair colour but the creamy, almost oily nature of caviar really brings this out, making the colour even richer and making it so much glossier. The eggs are packed with omega-3 fatty acids necessary for the formation of structural proteins. It is these proteins that repair dry and damaged hair and smooth over any split ends."

Her hair is washed with a truffle-based shampoo, and then smeared with the caviar, which is combed through and left to set. The sturgeon roe are liquidised prior to use, which is said to remove any odour.

The two-hour treatment also includes a complimentary glass of champagne and caviar canapes.