Exclusive: Valerie Bertinelli and Pat Harrington, Jr., Mackenzie Phillips' former "One Day at a Time" co-stars, are talking only to ET about the actress' drug arrest.

Valerie tells ET: "[Mackenzie] is a very good, good, sweet hearted woman who obviously is going through an amazingly difficult time. She doesn't need our judgment, she just needs our prayers."

"We both have an incredible amount of faith in Mack. Mack is a strong, wonderfully strong woman," Pat says.

"I love her, I love her to death," Valerie says emphatically. "She knows how much I love her, and I'm always there for her. Always."

Entertainment Tonight was behind the scenes with Valerie and Pat as they taped an episode of the Emmy-winning "Rachael Ray" show, which will air during the premiere week of the hit show's third season, starting on September 8.