Diane Keaton Had ‘Almost Childlike’ Energy Recording Solo Single (Exclusive)

Diane Keaton loved getting to record her first-ever solo single the year before her death at age 79, one of her longtime friends has said.

In an exclusive interview with PEOPLE, Grammy and Oscar-winning songwriter Carole Bayer Sager, 81, discusses teaming up with Keaton, who died in California on Saturday, Oct. 11, and co-writer Jonas Myrin to release the actress’s only solo track, “First Christmas.”

Sager tells PEOPLE of the song, which was released in November 2024, “I was just playing the song for my husband [Robert A. Daly, Board of Directors Chair at the American Film Institute]. We were listening to her sing this song [that] Jonas and I wrote and she loved it so much.” 

“She so loved recording this song and working with me and Jonas … she’d never stopped asking, ‘Are we gonna work on the song? Am I gonna sing?’ … She just was almost childlike about it. She was wonderful, she was wonderful. She was a magic light, you know, just for everyone,” Sager adds of her late friend.

Sager says she’s been questioning whether to re-release the single in Keaton’s honor.

“She sings about Christmas without you here, except when I listen to it now, she could be singing about herself, you know, which makes me very teary,” Sager admits. “She had a great life, and she touched so many people with her gift of acting and writing and even singing.”

“She just was a great light on this earth and loved life,” Sager tells PEOPLE, adding that it was “very shocking” to hear news of Keaton’s death.

Discussing how “First Christmas” came about, Sager recalled how Keaton told her “how much she loved to sing,” but didn’t consider herself much of “a singer.” 

“I said, ‘Well, maybe I can write you a Christmas song.’ So Jonas and I wrote this song. And then she came over and not only fell in love with it, she started crying as it moved her, and she said, ‘Oh, I love this, this is so beautiful,'” Sager remembers.

She continues, “So I said, ‘Well, why don’t you try and sing it?’ And she was so authentic when she sang it … she was sort of acting it, you know, because she is a great actress and, and then she’d start to cry when she was singing it.” 

“She did such a beautiful job on it, and she was always so insecure, [like] ‘are you sure? I could do it again? Should I do it again?’ ” Sager continues, insisting she’d tell her friend that her version was “perfect.”

Sager shares, “She always wanted to do it one more time and she could make it better … she was really obsessed with the song. She talked about it all the time.”

Grammy award-winning songwriter, producer and artist, Jonas Myrin, who co-wrote and produced “First Christmas,” also paid tribute to Keaton in a statement to PEOPLE.

“I’m heartbroken by Diane’s passing. To have been trusted to help bring her lifelong dream of recording an original song to life was a moment I’ll carry with me forever,” he says.

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Myrin adds how special it was to work on Keaton’s “final Christmas song,” noting, “That moment now holds profound meaning for me. In the studio, she filled the room with laughter and little jokes that kept us smiling.”

“I will never forget when she called me in tears, telling me that getting to sing this song was one of the greatest gifts of her career. It was a dream she had carried her whole life, to sing and record an original song, and being able to help her bring that dream to life was incredibly special,” he continues.

“Diane was fearless, curious, and full of heart in everything she did. Her voice, her heart, and her art will live on in those notes and in the legacy she leaves behind. And Diane will live on, forever in mine,” Myrin concludes.