The agency will handle all of its promotional activity across Europe.
Iris won the account, which includes western, central and eastern Europe including the UK and Africa and the Middle East, after a competitive pitch.
Iris will work with Unilever’s ice cream lead agency Lola – Lowe & Partners in Madrid as a promotional strategic partner to develop integrated campaigns for Magnum, focussing the brand’s long-term strategy on consumer engagement.
The first campaign will launch in early 2011.
Separately, the brand has signed up Hollywood actor Benicio del Toro, star of ’The Wolfman”, as the face of a £3m advertising campaign which launches this month.
Last year, Magnum faced problems when a £1m summer promotion to giveaway MasterCard pre-loaded cards was oversubscribed and Unilever was forced to delay giving out prizes.