Tomorrow at 10am at their Flagship store, 311 Oxford Street, London.
Here's a copy and paste of the email:
When it's cold enough to wake up in the morning and find a delicate web of snowflakes in the corner of your window, let the layering begin. Our HeatTech innerwear is woven out of a specially designed hollow fibre thread that captures little pillows of toasty warm air, insulating your body in the same way a heavier wool would and creating a secret weapon against the winter chill.
To help you beat the winter chill, we're giving away free Heat Tech gift packs* each worth nearly £20, tomorrow from 10am at our Flagship store, 311 Oxford Street, London.
There are 4,000 gift packs to give away and all you need to do is look out for the HeatTech team - you won't miss them, they'll be dressed in silver jumpsuit's toting thermal imaging cameras, anyone they think is cold enough will receive one of these HeatTech gift packs!