The Australian shopping centre company, which owns the £1.6bn White City complex that opened in 2008, appointed the agency after a final shootout against Leo Burnett.
CHI will replace Adam & Eve, which was appointed to the £5m advertising account. in 2008 but resigned it in order to handle the £20m John Lewis ad account.
On its launch in October 2008, Adam & Eve put together a multi-million pound, integrated marketing campaign to mark the shopping centre’s grand opening.
Alongside a TV commercial, the campaign also included partnerships with glossy weekly magazine Grazia – which edited its magazine live from Westfield.
The news comes shortly after it emerged that Leo Burnett executive creative director Jonathan Burley announced he was leave the agency to join CHI & Partners.
Burely will replace Ewan Paterson, the executive creative director of CHI & Partners, who announced his departure days ago to take control of the creative department at DDB Chicago.