The Leicester Square-based hotel, part of the global W Hotels group, made the appointment after a pitch process, replacing incumbent John Doe.
The contract will see W Communications drive greater connectivity with the luxury hotel and its key audiences across fashion, design, music and film.
The first project will involve promoting a global film partnership with Intel that is fronted by film director Roman Coppola, called Four Stories.
Warren Johnson, founder of W Communications, said: 'This is about making the location a landmark in London a real hub, not just for the local community but also for global travellers in the word of design, fashion, film or music.
'That’s whether it’s Nicki Minaj - who has stayed at the hotel in the past - or film producers meeting to discuss their scripts. The proximity it has to Leicester Square and the great screening room also means it makes sense to dial up its relationship to the world of film.'
Helen Leighton, area director PR, UK & Ireland for W Hotels, said: 'Our objective is to bring strategic partners to the table from the fields of fashion, design, music and film that offer brand synergy, press-worthy elements and unique insider experiences for our guests. We also want W London to become part of the cultural fabric of Leicester Square - a landmark in the city that locals and visitors alike can relate to.'
W Communications' appointment comes after a parting of ways with John Doe, which did not repitch for the work.
Rana Reeves, founder of John Doe, said: 'John Doe has enjoyed handling the launch phase for W London alongside our work across different properties. We smashed our deliverables and delivered a hot launch phase that put the hotel on the map culturally and commercially.
'It is agency policy not to repitch business when we think a rebrief should have happened and we did not take part in the pitch. While Starwood were disappointed they accepted our decision. We wish our successors luck and look forward to seeing the coverage.'
W Hotels has 42 hotels globally, including Barcelona, New York and Beijing, and is owned by Starwood Hotels & Resorts.