Michelle Pfeiffer has revealed her racist 'Hairspray' character upsets her children.The 'Batman Returns' actress - who has an adopted mixed-race daughter Claudia Rose, 14, and a biological son, 13-year-old John Henry, with her 'Ally McBeal' creator husband David E. Kelley - says her kids could not understand why she was playing "vile racist" Velma Von Tussle. Pfeiffer said: "It was a shock for them because they saw me out of context and they said, 'Mom, what are you doing?' They really didn't know what to think because they don't have a frame of reference for a movie set in the 60s. I don't think they thought it was all that cool."The film focuses on a group of teenagers on a 60s televised dance show in Baltimore, which discriminates against black contestants.The 49-year-old actress admits it wasn't just her kids who were shocked by the character - she even upset herself. She said: "There were some lines I honestly could not remember because they were so hateful. I'd be doing a scene and I'd come up blank. It was interesting what my brain did."'Hairspray' also stars John Travolta, who dressed in drag for the role of Edna Turnblad, the mother of one of the dance contestants.