The pair have previously worked together on the 'Girl Gone Wild' hitmaker's clothing range Material Girl, and the singer has been advising the 'Fashion Police' host on diet and exercise to drop a dress size, reported Contactmusic.
"Madonna's helped Kelly get back to a size eight. Kelly does the Ballet Barre workout five days week - she loves the dance element and can see how it's changed her shape.
"Madonna's also encouraged her to eat in a more macrobiotic way - cutting out wheat, artificial sweeteners and cheese. Kelly's avoiding carbs to beat bloating and has been eating boiled eggs for breakfast, grilled chicken salad for lunch and fish with steamed greens for dinner," a source said.
