The retail section of the ultra-modern station is taking shape in preparation for the arrival of the first High Speed 1 trains linking London to Paris and Brussels in three months time.
Dave Meekings, Hamleys' international development manager, said: "As part of our strategy to develop our travel-related stores, we decided to take our first railway store at St Pancras. The station will give us great exposure to a large number of both business and leisure travellers. It's going to be a very exciting hub for us.
"We know from the success of our airport stores that travellers are excited by the fun and magic that Hamleys has to offer. We've got something for everyone whether it's presents to take home for the kids or games, toys and puzzles to keep them occupied on a journey."
The shops will be located at platform level and in the under croft, formerly a Victorian beer store, at the Grade 1 listed station, which is expected to play host to an estimated 50 million visitors by 2009