As the industry watches WPP following the exit of chief executive Martin Sorrell, the world's largest advertising holding company notched a success, retaining the global work for BP's corporate, fuels and Castrols businesses. It's a new style of relationship with its longtime client.

"As we enter the third decade of our relationship, we have agreed on a completely new way of working to enable easy access to the best talent and ideas that WPP has to offer," Geoff Morrell, group head of communications and external affairs at BP said in a release.

"Team Energy" will provide advertising, media investment management, digital media, marketing communications, branding, PR and brand research from WPP agencies including VML, Ogilvy, Mindshare, Grey, Essence and others, WPP said in a statement. Its new "flexible media model," called "EnergyMedia," will also combine talent from WPP agencies.

The holding company is currently working to defend some of its major clients, including Ford — where the holding company's own bespoke Global Team Blue is at stake — as well as Mars, Shell and GlaxoSmithKline.

BP and WPP have been working together for the last 20 years, with WPP working on the development of BP's Helios logo and a number of campaigns. The holding company says the decision comes after a competitive review.

Andrew Scott, co-chief operating officer at WPP, said the redefined relationship reflects how the holding company sees the future — "delivering agile, responsive and impactful services that drive results and help realize the client's growth ambitions."