Fashion is an expression of cultural trends on many levels, including gender roles, social and political upheaval, world events, growing awareness or and curiosity about foreign cultures, and shifting attitudes in morality. One trend that has been strongly affecting fashion since the 1940s has been the infuence of celebrity icons. The Hollywood star system had a significant impact upon popular fashions, since Hollydoow designers would design clothing exclusively for actresses (both onscreen and off) and create unique and inspiring looks that moviegoers aspire to emulate. These days, constant media exposure of celebruty culture ensures that celebrity fashion choices are always in the pop culture mainstream. Musical performers like Madonna, Michael Jackson and Lady Gag, just to name a few, have engaged fashion and unusual modes of dress into their performances and made clothing and costumes a central feature of their personae.