The changes follow the appointment of Mark Read, the chief executive of WPP Digital, as chief executive of Wunderman in January.
Spirit will also continue in his role as chief strategy officer for WPP.
As chief digital officer, he will take over Read's responsibility for digital strategy, coordination of digital resources for clients, partner relations and WPP's digital conference, Stream.
Singapore-based Spirit has been chief strategy officer for WPP since October 2010. Prior to that he was strategy director for China and Asia Pacific starting in 2006. He made Campaign Asia-Pacific's "40 under 40" list in 2013.
As chief operating officer of WPP Digital, Povey will work with Read on developing the WPP Digital companies while also continuing in his role as WPP general counsel.
This story was first published by Campaign Asia-Pacific.