Around 400 people were evacuated from the hotel on Portman Square, following the blast just before midnight on 21 November. Despite widespread damage to the kitchen, there were no serious injuries.
Among the first visitors to the hotel were relatives of Sir Winston Churchill, after who the hotel is named. To celebrate its re-launch, the hotel is running a series of Churchill Commemorative promotions including the newly created Never Give In cocktail (pictured) and tickets to the Churchill War Room, the bunker that sheltered Churchill and his government during the Blitz.
Michael Gray, general manger of the five-AA-star, 434-bedroom hotel, said the hotel was "thrilled" to be back up and running and looking forward to welcoming guests again.
Around 150 bedrooms are now operational again, alongside all the public area, including the Churchill Bar & Terrace, the Montagu restaurant and the one-Michelin-star Locanda Locatelli overseen by Giorgio Locatelli.
Hyatt has used the closure of the hotel to kick start a multi-million pound renovation, overseen by interior designer DeSallesFlint, of many of the bedrooms and suites.