Mackenzie Phillips is an American actress and singer, best known for her role as Julie Cooper on the popular television series One Day at a Time. Born on November 10, 1959, she comes from a family with a strong musical background, as her father is John Phillips, the lead singer of the band The Mamas & the Papas. In addition to her acting career, Mackenzie has faced personal challenges, including struggles with addiction. She has written about her experiences in her memoir, shedding light on her journey to recovery and the impact of her family's legacy in the entertainment industry.