Broadcaster wants to "reward" its social audience through new push.
Capital Radio is playing with hidden content on Instagram to promote its Jingle Bell Ball concert.
The new format invites followers to 'ReGram' celebrity images from Capital's feed and use Instagram's native filters to reveal secret messages.
The photos will run ahead of the event tomorrow (6 December). Justin Beiber, Calvin Harris and Little Mix are among some of the names headlining the annual show, and the Global-owned brand said it wants to put "audience reward" at the heart of the campaign.
All artists featured on Instagram will be performing at the gig and the content revealed via the filters are real quotes collected through interviews.
Social Life devised the idea and co founder Laura-May Coope said that the agency chose Instagram because it is the "perfect platform for a young audience engaged with pop music," as well as a strong destination for "fandom interaction".
Coope said the social shop took a similar approach to exclusive and rewarding content with Capital's Summer Time Ball, which saw the account's followers grow by 82 per cent in just 24 hours.
"Using filters to reveal secret messages is a really new behaviour, and we know a very engaged global audience love playing with these elements, and sharing the results," she added.
Ted Baker took a similar approach earlier this year with its Instagram 'Treasure Hunt'.