The agency won the business following a competitive pitch. It has been briefed with launching a global launch campaign for the new brand, which is backed by seven conservation organisations led by The Royal Foundation, and has created its logo and website.
James Murphy, the chief executive of A&E/DDB, said: "We are thrilled to be working with the Royal Foundation to make United for Wildlife a brand that inspires a young generation to engage with wildlife in a truly meaningful way."
The Duke and Duchess of Cambridge and Prince Harry set up The Royal Foundation as the focus of their charitable activities.
Nick Booth, the chief executive of The Royal Foundation, added: "Working with Adam & Eve/DDB has been a refreshing experience.
"The combination of creative excellence and technical expertise Adam & Eve/DDB possess has meant the partnership between United for Wildlife, The Royal Foundation and Adam & Eve/DDB is delivering great work, and we’re excited about continuing to develop this campaign."