The agency has been chosen to look after consumer and lifestyle work as the store launches its assault on the Christmas market.
The news follows the departure of LightBrigade MD Alan Twigg from Seventy Seven PR in September, where he handled the client for several years.
Twigg said: ‘Hamleys came to us and asked if we would handle the campaign for them.
‘We will be making sure that we help with what will be a big showcase event on site in July.
‘Christmas is a significant part of Hamleys’ success, so it’s a big deal.’
The six-month brief will see LightBrigade launching to long lead media in July and continue through the Regent Street store’s major refurbishment this summer.
Broadcast and consumer press are expected to be particular targets.
The brief will include supporting Hamleys’ Glasgow and Dublin stores, as well as the company’s growing international estate, from the Middle East to India.
The team will report to Hamleys’ retail director Nigel Wheatley and CEO Gudjon Reynisson.
Twigg left Seventy Seven PR as part of a senior-ranks walkout in September.
His departure came alongside that of fellow managing partners James Gordon-MacIntosh and Jo Carr, who went on to set up Hope&Glory.