The discount retailer picked the entertainment specialist following a five-way pitch.
Taylor Herring will devise a campaign particularly focusing on regional press around the chain's 214 nationwide stores. TV, radio and online media will also be targeted.
The agency will promote the sale of the official Red Nose Day T-shirts, designed by Stella McCartney.
The T-shirts feature iconic portraits of the Beatles by Linda McCartney, Morecambe & Wise by David Bailey and a rabbit by Mary McCartney.
Part of the campaign will involve giving iconic statues across the UK a 'Red Nose Day makeover' and using this as a way of raising awareness.
The account will be led by Siobhan O'Connor who reports to TJX Europe PR manager Victoria Wright.