Mary Tyler Moore says she is "absolutely devastated" by Valerie Harper's diagnosis with terminal brain cancer. She tells People magazine, "Valerie has given so much joy, laughter and love to the world. I join her fans and send much love and positive thoughts to her and her family during this difficult time."

Harper says she called her long-time friend and former co-star on Tuesday, the day before revealing her dire medical condition. "After small talk, she said, 'What's up?'... I said, 'It's incurable cancer.' She said, 'Val, I'm so sorry'." She also recalled Moore -- whose son and sister have both died since the days of her iconic sitcom -- writing about Harper in her memoir: "In one of her books she said, 'At every funeral of my family, Val was at my side. It's true. I love her."

Mary's advice to Valerie was simple: "One day at a time. That's how we've got to live our lives. That's the best we can do."