George Clooney's Italian girlfriend Elisabetta Canalis is at the centre of a wide-ranging sex and drugs scandal involving businessmen, celebrities and high-class prostitutes.

It is believed that Canalis, a former showgirl, took cocaine at a nightclub in Milan that is now under an investigation into an alleged prostitution ring in which rich clients enjoyed the favours of high-class escort girls while taking drugs.

In court documents released in Milan this week, a French escort girl has testified that she saw a number of young models and starlets, including Canalis, taking cocaine at the clubs.

"I used cocaine along with other people, among whom was Elisabetta Canalis," the Telegraph quoted the French woman, Karima Menad, 26, as saying.

Her evidence forms part of a dossier, which has been put together by prosecutors on the alleged prostitution ring.

The investigation into two Milan nightclubs - 'The Club' and 'Hollywood' - resulted in the arrest of five people on Monday and the closing down of the two nightclubs.

The allegation dates back to 2008, a year before Italian Canalis,31, started dating Clooney, 49, who owns a luxury villa on the shores of Lake Como, north of Milan, and spends a considerable amount of time in Italy.

The Italian press has speculated for months that Clooney, one of Hollywood's most popular and respected actors, might be about to propose marriage to her. (ANI)