The agency, which was chosen after a competitive pitch against three other firms, has been appointed for a year-long programme.
Setting up "an effective press office function with all the impactful fundamental collateral" is among its initial priorities, according to Angie Wiles, founder of The Difference Collective.
Heart UK campaigns to prevent premature deaths from high cholesterol – a major risk factor for heart attacks and strokes.
Jules Payne, the charity’s chief executive, said: "The team at The Difference Collective showed unrivalled expert knowledge of the health media landscape, a huge amount of relevant insight and senior talent, as well as real passion for our charity. We felt they would be the perfect partners to help us raise the profile of Heart UK."
She added: "Over half of UK adults have raised cholesterol, which can lead to heart disease and strokes, yet too few people know about it or how dangerous it can be. We believe The Difference Collective are the best team to help us expand our reach and raise awareness of the vital importance of high cholesterol and how to tackle it."
Former ITV News journalist Elspeth Massey, head of charity at The Difference Collective, will lead work on the new account.
She will be supported by Jo Willey, former health editor at the Daily Express, and collective media maestro at the agency.
Wiles commented: "Everyone at Heart UK works tirelessly to increase awareness of high cholesterol [and] the terrible health dangers it can cause, and is a major force in campaigning for change."
She added: "We’re delighted to have been chosen as their agency to increase their media relations activity. Elspeth and Jo are two of the best in their fields and we know we can help Heart UK with its ambitious plans. We are incredibly excited about our future work together."
The Difference Collective’s client base includes Allergan, AstraZeneca, Boehringer Ingelheim, Roche and Santen.
In recent months it has been appointed by HRA Pharma to provide PR and social media support for Compeed blister plasters, while Perrigo UK has selected the agency to manage its 2019 trade PR programme, including key brands such as Solpadeine, NiQuitin and Nytol.
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