Vizeum, previously known as BBJ, won the business after a pitch against the incumbent agency, Walker Media, and MediaCom.
Walker Media had worked with five since 1998, when it won the account from Carat.
The pitch process was overseen by David Pullan, five's director of strategy and marketing. Pullan was looking for an agency that combined "top-quality buying" with an understanding of the five brand and able to generate "ideas that provide the extra sparkle that make campaigns connect and cut through the clutter".
Vizeum will work alongside five's creative agency, TBWA\ London, and the below-the-line specialist The Promotions Factory.
"We chose Vizeum because we are looking to broaden our communication strategy with audiences and to develop further the creative thinking element of our media strategy," Pullan commented.
The five account will be headed by Trista Grant, the managing director of Vizeum. Matt Andrews, the new head of strategy at Vizeum, also played a part in winning the account.
Andrews said: "Five is exactly the type of proposition that Vizeum was designed for. It is leading the way in its approach to marketing and we relish the opportunity to partner the channel and TBWA\ London into 2004."
Pullan praised Walker Media for its work on the five brand. He said: "I'd like to thank Phil (Georgiadis) and the team at Walker Media for their excellent work over the past five years and their substantial contribution to the success of marketing for Channel 5 and five."
The loss of the five account follows the move of the £14 million Freeserve business out of Walker and into Initiative Media. However, the agency made up for this loss with the capture of the £16 million KFC account from ZenithOptimedia.