The agency has been briefed to lead all comms for The Global Party, a series of 180 events for VIPs that it is hoped will raise £2m by the end of 2014.
The agency, appointed after a non-competitive pitch, is being tasked to find a media partner for the events and manage publicity and overall brand comms for the initiative.
Creative director Alon Shulman of Worldwide Exposure pointed to the "variety of locations and events" involved in the invite-only fundraisers as part of their attraction.
These include the Orient Express and a hot air balloon outside London’s Natural History Museum.
Formed in 2011, The Global Party has grown from being a two-day event for 80,000 to next year expecting 360,000 across 160 cities, attracing stars such as Uma Thurman, Arpad Busson, Lily Cole, Bryan Ferry, Macy Gray and Hayden Panettiere.