The agency has been briefed to increase awareness and understanding of the La Senza brand and its 190 stores in the UK and Ireland. At the same time, Diffusion will look to drive traffic to boost online sales.
Situl Thakrar, head of online for La Senza, said: 'We want to use social media as a way of providing insight to the rest of the business, which is where many multi-channel retailers fail.
'Our continued investment in digital reflects our desire to position La Senza as a leader in online innovation in the lingerie segment. It shows the ability for social media marketing to amplify our brand and commercial opportunity.'
Diffusion plans to use social media to emphasise La Senza's affordable luxury values and product range. The agency has also been asked to highlight the brand's expertise and service - both in shops and on the web.
Diffusion will set about building and managing a brand presence for La Senza on key online platforms, including Facebook and Twitter, in a bid to create conversation platforms. It will also run an ongoing influencer-relations campaign, with features such as key fashion and lifestyle blogs and forums.
Ivan Ristic, director and co-founder at Diffusion, leads the account.