Demure Katy Perry covers up her curves with a WWII-era military uniform for VH1's Salute the Troops

By DAILY MAIL REPORTER Happy to give back: Katy Perry and Kathy Griffin are all smiles as they pose in military costumes they donned for VH1's Divas Salute The TroopsNormally Katy Perry likes to show off her womanly curves.But a new picture on Twitter shows the chart-topping singer dressed down and completely covered up for VH1's Divas Salute The Troops.Katy, 26, posted the picture of herself