Thompson will take up his new post on October 29 and will replace Tim Sefton who has been appointed O2 senior VP strategy and development.
Thompson has 13 years of experience in advertising agencies and has overseen successful global launch campaigns for PlayStation 2, Strongbow, Ask.com and 3. He was also led the team that created the widely known Guinness good things come to those who wait campaign.
O2 customer Director Cath Keers said: Gav joins us at an exciting time, when O2 has established its place as the UKs leading operator both in terms of customers and in brand leadership.
I am pleased we have been able to find someone whose experience, passion and commitment is a match for ours.
Thompson added: O2 are clearly the thought leaders in their market space. The opportunity to help shape one of the great brands of the twenty-first century is hugely exciting and I cant wait to get cracking.