The campaign will go live in January and run through to the games, which run alongside the Sport Relief event on 18-20 March 2016.
The aim is to inspire people to sign up and choose to run, walk, swim or cycle to raise money for Sport Relief.
Michele Settle, director of UK campaigns and brands at Comic Relief, said: "House PR’s dedication to Sport Relief really came across in the pitch, and we can’t wait for them to get started and encourage the UK public to get involved in the Sainsbury’s Sport Relief Games and raise money to help people here in the UK and across the world’s poorest communities."
Ginny Paton, managing director of House PR, added: "We are thrilled to work on such an amazing campaign and charity. Our ideas have been crafted to inspire the public to sign up and get involved with the Games – and particularly to talk to people that wouldn’t necessarily consider themselves to be 'sporty'. There is something in this year’s Sport Relief for everyone and the PR will reflect that."
Since 2002, Sport Relief has raised more than £95m. The money raised is spent by Comic Relief to help people living incredibly tough lives, both in the UK and across the world.
Comic Relief continues to work with a roster of agencies including Cowshed for regional press.
Last year, Comic Relief's head of media said that Sport Relief campaigns were about finding "a balance between entertaining or sporty content and the real and often harrowing stories about the people the money raised helps".