SHE is as renowned for her wholesome image as for the chart-topping hits that have made her one of the highest-paid pop artists in the world. But Beyonce has revealed that she prepared for her latest movie role by spending hours in rehab with recovering heroin addicts. In Cadillac Records, the 27-year-old superstar plays troubled soul diva Etta James. Etta was hooked on heroin by the age of 21, posing a problem for Beyonce, who has never experimented with drugs. The singer asked a New York substance abuse charity to help and it arranged for her to meet six African-American women whose lives had been wrecked by heroin. They taught her everything from the secrets of 'the junkie stagger' to their 'addled rage'. Beyonce explained: 'I said, "I have to do this movie'' - but I was terrified. 'I never tried drugs in my life so I didn't know about it all. 'It was hard to go to the rehab. I learned a lot about life and myself.' The star broke down in tears several times. " DM Beyonce also met Etta James. Now 70 and reformed, the soul legend's life was out of control by the Seventies. The movie will be released in the UK next spring. DM