Green was head of PR for O2 for the past nine years and will now take responsibility for the parent company's PR, social media, public affairs and internal comms.
She said: ‘As a leading and ever-evolving comms brand, these are exciting times for O2. I am delighted to have been asked to lead the wider team and excited by the challenge to ensure O2’s comms are front of mind, both internally and externally.’
Green will report to Telefónica UK’s CEO Ronan Dunne.
She was previously a UK campaigns manager for Orange and brand manager for Dr Pepper, part of Schweppes Beverages and Coca-Cola UK.
Telefónica UK is currently on the hunt for a PR and public affairs agency to build awareness of Telefónica’s digital strategy, establish its credibility in the digital world and change perceptions of Telefónica as just a telecoms company.