Beyonce Knowles was so moved by the plight of the recovering drug addicts she met while researching her new film Cadillac Records, she broke down in tears.

In the upcoming movie, the clean-cut Bootylicious beauty portrays soul legend Etta James, who battled numerous drug issues throughout her life. And to get into character, Knowles visited a rehabilitation clinic - so she could better understand the struggle faced by addicts.

The singer/actress contacted a New York-based substance abuse charity to arrange a meeting with six African-American women whose lives had been turned upside down by heroin.

But she didn't expect the visit to the Brooklyn drop-in centre to be so emotional.

She explains, "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 rehab. I learned a lot about life and myself."

The charity's chief executive, Howard Meitiner, adds, "It was very intense. Everyone was crying. These were women who have lost everything because of drugs - their homes, their families, their jobs."