The aim of the project is to provide a platform for development of new digital services and enable greater collaboration between the firm's various brands.
It will also allow the firm expand the use of big data and analytics to help drive decision making.
WPP has grown quickly through acquisition to encompass 300 companies, and recently put Robin Dargue in place as its Group CIO to help unify and transform its IT.
"As the world's largest communications group, we are seeking to exploit IBM's cloud computing expertise to allow us to innovate and add value to both the service and the product we deliver to clients across 111 countries" said Dargue.
The investment in on-premise and public cloud resources is part of an extension of existing services relationship with IBM.
The outsourcing firm has announced a number of large services deals in recent months, including a £1 billion deal with German airline Lufthansa, and a 'multi-billion dollar' ten-year contract with Dutch bank ABN Amro.
IBM has ramped up its cloud offerings since buying infrastructure as a service provider Softlayer last year. It has also invested in expanding its reach, with a new data centre announced in London.