Fashion designers Domenico Dolce and Stefano Gabbana, who supply clothes to some of the world's most famous models and celebrities, have been sentenced to a year and a half in jail in Italy for failing to declare €1bn (£833m) of earnings.

The pair are behind the luxury Dolce and Gabbana label, which is based in Milan. Neither man attended the trial and they both deny the charges and have appealed.

The jail sentences will be suspended pending the appeal outcome. The court also handed down a suspended fine of €500,000 (£429,000) to each man.

Italian authorities say they began investigating the designers about six years ago as part of a crackdown on tax avoidance. In court, it was claimed that in 2004 Dolce and Gabbana moved their brand to a Luxembourg-based holding company called Gado - a play on their surnames.

The tax authorities argued that Gado was no more than a shell company and that this was a sham move, designed to avoid declaring taxes of about €400m (£342m) on royalties of around €1bn (£833m).

Dolce and Gabbana were initially cleared of the charges at a previous trial in April 2011 but Italy's highest court overturned that ruling, ordering that the case should be sent back. The appeals process is likely to take some time, during which period the designers will remain at liberty.