Hilton London Euston is carrying out an £8 million refurbishment that includes all of the hotel's 150 guestrooms.
The work will also see "a number of new bedrooms" added and a new fitness centre.
The first revamped guest rooms in the Bloomsbury property will be available from next month.
The hotel will remain open during the refurbishment and the work is expected to complete in the second quarter of 2016.
A statement said: "The new design of the guest rooms is inspired by the heritage of the surrounding area which is well renowned for its culture, literary, artistic and social links in the 19th and 20th centuries."
In June, Hilton Worldwide opened its 11th Doubletree hotel in London (see news, June 28).