We all know that mice love cheese. Rather than obtain a license to use, say for example, Speedy Gonzales, Borden opted to create their own rodent(s).
What they did was hire an anonymous actress, and dressed her in a grey & white mouse bodysuit to do a series of spots for Lite Line cheese. As the brand name implies, this has fewer calories than regular sliced cheese.
In this 1980 spot, Borden's ad agency upped the babe quotient by adding a few extra "mice" at the end.
Unfortunately, Lite Line is not around anymore, and, for that matter, neither is Borden, which discontinued Lite Line and other food products a few years back, while other familiar brands, such as Wyler's juice mix and Cracker Jack, were sold off to other companies. Wise potato chips was spun off into its own company.