Mackenzie Phillips has revealed that during breaks while filming the sitcom "One Day at a Time," she and co-star Valerie Bertinelli would drink wine and use cocaine. Phillips, who was 15 when the show began and Bertinelli was 14, described driving to her house, getting in the pool, and using drugs during lunch breaks. Phillips clarified that Bertinelli has spoken about this period herself and did not have the same level of addiction Phillips struggled with. Phillips noted that drugs were present in the dressing room as well, and she was the one who was caught. The actresses, who played sisters on the CBS sitcom from 1975 to 1984, have maintained a close friendship over the years, with Phillips crediting her faith and resilience for her ability to discuss her past.