Difference between Pinot Grigio and Pinot Gris

After using Pinot Grigio in one of the classes, there was debate about whether Pinot Grigio and Pinot Gris were the same grape or whether they were slightly different strains of the same grape. I have made a few enquiries and all information seems to stem to the fact that it is the same grape - named Pinot Grigio in Italy (and Australia) and Pinot Gris in France. It is a strain of the Pinot Noir grape and each country has their different style of winemaking.