The agency has won the account after a contested pitch, handled by AAR, against four other agencies.
Johnny Fearless' task will be to develop a new strategy and creative campaign for the Imperial War Museum London – the flagship branch. The museum, which is closed for refurbishment until July, is seeking to promote its First World War galleries, which launch next year to mark the centenary of the conflict.
Penny Hamilton, the head of brand and marketing at Imperial War, said: "Johnny Fearless were true to their name, presenting a breadth of work that had both sensitivity and bravery in equal measure".
Other agencies to work with the museum in the past include The Good Agency and Ogilvy & Mather. The latter won awards in 2007 for its poster work for the museums.
This article was first published on campaignlive.co.uk