The relaunch includes new TV ads, packaging and a revamped logo.
TV ads will launch in November. The campaign will also run print, radio online campaigns.
Dairy Crest said the move will strengthen the brand's position as the leading cheddar brand in the £2.2bn cheese category.
The company added the Cathedral City brand is worth more than £190m.
Laura Downey, Dairy Crest head of marketing for cheese, said: ‘We are investing significantly in this relaunch as we know that our growth has come from continuous investment throughout the brand's history.'