Originally designed by architect Lewis Cubitt, the 91-bedroom, Grade II-listed property was closed in 2001 to make way for the Channel Tunnel rail link and improvements to King's Cross Station and St Pancras International.
Owner Jeremy Robson of asset management company Ram said that he is confident the crescent-shaped hotel will perform well, despite the burgeoning five-star hotel market in London.
"The hotel's strategic location at the heart of what is the biggest railway hub in Europe, with 135 million passing through annually, is hugely significant," said Robson.
"Combined with the sympathetic renovation of what is a beautiful building - incorporating elegance and grace with a hint of modernity - I am certain that the hotel will do well.
"The success of the nearby St Pancras Renaissance has proved that there is demand for high end hotels in the area."
Archer Humphryes Architects has created a new interior design which is intended to evoke the romance of rail travel from a bygone age, with three room types: Couchettes (emulating train sleeper compartments), Wainscot (named after the walnut Wainscot panelling) and Cubitt (for the original architect).
Great Northern will feature a 90-seat restaurant, Plum + Spilt Milk, serving classic British and European dishes such as twice baked smoked haddock soufflé, spring lamb hot pot with minted pea and broad bean salad, tarte tatin and lemon meringue pie.
It will also have two outlets with direct access onto the new western concourse of King's Cross Station: the GNH bar and the Kiosk, serving hot roasted, pulled-pork sandwiches.
Robson intends to roll out the Kiosk concept to other locations throughout London with a high footfall, including other railway stations. "Kiosk will serve generously proportioned food of a great quality that has not previously been seen in stations in this country," he said.
Robson said that with just 91 bedrooms, there was no need to take on board branding from one of the large corporate hotel companies, but he is considering joining one of the key marketing consortia.
Hotel director is Marie Rodini and head chef is Ray Patterson. Room rates start at £250.
London's Great Northern to be revamped as boutique hotel >>