The sponsorship covers the interactive lunchtime show, where listeners request the music they want to hear during their break.
The show airs each weekday from 1pm on GWR's Mix network of stations, which includes GWR Bristol, Leicester Sound, Essex FM, Trent FM and Beacon FM.
The deal includes sponsorship credits, bespoke programming content, online activity, promotions and sampling. The aim is to bring the fast-food snack's 'super' brand positioning to life at a time when listeners are deciding what to eat for lunch.
The deal was brokered between ZenithOptimedia, Naked and Opus Sponsorship, GWR's sales house.
Separately, GWR is launching what it claims to be the world's first radio music download offering this week. Listeners who log onto the station's web site from later this month will be able to download the track currently playing and copy it onto a CD.