The agency won the business after a pitch and will work to raise the brand's profile across the UK and Europe.
Triumph, which has used the TV presenter Louise Redknapp as its spokeswoman, is to launch its first ecommerce site across Europe, allowing consumers to buy any of the brand's underwear online for the first time. The activity will be handled by Wunderman.
The lingerie brand has handled the bulk of its digital account in-house but used agencies in different markets on an ad hoc basis. In the past, Triumph has used Ogilvy & Mather on its pan-European creative account and Landround on promotions.
In recent years, Triumph has carried out a number of marketing stunts, including a fashion show to coincide with the premiere of 'Sex And The City 2'. It was supported by a cinema ad, foyer activity and postcard competition.