Robert Downey Jr. reportedly had been using drugs for six weeks prior to his Thanksgiving arrest in Palm Springs on cocaine and methamphetamine possession. According to next week's People magazine, the troubled Ally McBeal thesp even left his seven-year-old son, Indio, alone one night so he could go score with a dealer, leading his estranged wife, Deborah Falconer, to ban him from seeing the child. Meanwhile, the Los Angeles Times reports that Downey has been dropped from the upcoming romantic comedy, America's Sweethearts, co-starring Julia Roberts and Catherine Zeta-Jones. A replacement is being sought. Downey — who was hospitalized over the weekend for depression — faces a Dec. 27 probation hearing that could land him back in the slammer.