Diesel's US chief executive Pan Philippou is returning to the UK in September to become chief executive at brand house WDT.
WDT owner Asbed Momdijan told Drapers the move was part of a bid to grow the company's international status.
Philippou will take over from Momdijan, who has been running the business but will step up to a chairman's role at WDT, which owns Firetrap and Sonneti.
"There are opportunities for us overseas and we need someone with Pan's skills to help us. He has a lot of international experience across wholesale and retail," said Momdijan.
The group is recruiting for three new senior posts to support Philippou, but Momdijan would not comment on the details.
The move coincides with a deal to open WDT's first overseas stores. Momdijan has signed a seven-store franchise partnership with Dubai-based Paris Group, and the first shops will open in Dubai's Festival Hall mall in October.
"This is our first franchise agreement," he added. "It is a significant move as there is a big opportunity for us in the Gulf. The openings will be phased over the next three years, with our second store set to open in spring 08."
WDT is forecasting turnover of £80 million for the past financial year.
International sales make up 30% of WDT's business. The group is represented in 18 overseas markets, the strongest being Italy and Germany, where it has its own subsidiaries.