News of the venture emerged on 29 November, but WPP has only now spoken publicly about the plans.
The marcoms group, owner of agencies including Burson-Marsteller and Finsbury, will take a minority equity stake in Global Counsel.
It has provided seed capital along with additional benefits in kind including office accommodation.
A WPP representative will sit on Global Counsel’s board alongside chairman Lord Mandelson and managing partner Ben Wegg-Prosser.
A statement sent out by WPP said Global Counsel would ‘provide corporate leaders with support to grow their businesses beyond their home markets’.
WPP CEO Martin Sorrell said: ‘Peter’s experience, skills and know-how made this an opportunity that was too good to miss. We are looking forward to supporting him grow Global Counsel into a world-class advisory business.’
Lord Mandelson said: ‘This is an exciting project and I am thrilled that Sir Martin has backed our new venture. I’m looking forward to getting behind my desk and working alongside businesses whose values I share to help them develop in an ever-changing world.’
