Seventy Seven PR will handle consumer work for the Baugur-owned toy retailer, including the press office, seasonal campaigns and new product launches.
Hamleys has worked with agencies previously on a project basis. Most recently it worked with Resonate, which took on projects last year for Easter and the September toy awards.
Hamleys' PR manager Charlotte Chisnall said that although Seventy Seven would be handling consumer work, its link to Fishburn Hedges was attractive because it meant that it could offer other types of PR support if required in the future.
Hamleys is opening a store in Jordan in April and is set to do the same in Dubai, India and China.
Despite difficult market conditions it received an 11.3 per cent increase in like-for-like sales over the Christmas period.