Diane Keaton‘s longtime friend and collaborator reflected on her final visit with the actress … recalling how she was struck by Keaton’s noticeable weight loss in the weeks before her death.

In an interview with PEOPLE, Carol Bayer Sager says she saw the Oscar winning star just two or three weeks ago and was surprised by the change in her appearance. “She was very thin,” Sager shared. “She had lost so much weight.”

According to Sager, Keaton had spent much of the year in Palm Springs after wildfires damaged her California home, and the two friends hadn’t seen each other as often. “When she came back, I was kind of stunned by how much weight she’d lost,” Sager said, adding that despite the physical changes, Keaton’s creativity and spirit were as vibrant as ever.

“She was a magic light for everyone,” Sager said. “She was upbeat and always creating — taking photographs of everything, just completely engaged in life.”

The two last worked together on Keaton’s holiday single “First Christmas,” released in late 2024. “She loved recording it,” Sager remembered. “She sang with so much heart, she even teared up during the session.”

“She was such an original,” Sager said. “There was no one like her.”