As tributes continue to pour in for longtime Fleetwood Mac singer/keyboardist Christine McVie, who died Wednesday at 79 after a brief illness, her former bandmate Lindsey Buckingham posted a touching tribute to her on social media.

Christine McVie’s sudden passing is profoundly heartbreaking. Not only were she and I part of the magical family of Fleetwood Mac, to me Christine was a musical comrade, a friend, a soul mate, a sister. For over four decades, we helped each other create a beautiful body of work and a lasting legacy that continues to resonate today. I feel very lucky to have known her. Though she will be deeply missed, her spirit will live on through that body of work and that legacy.”

The post includes a handwritten note that was similar to that of the group’s Stevie Nicks, which was posted Wednesday.

That classic lineup of Fleetwood Mac was famously fractious, as Nicks and Buckingham and McVie and her first husband John McVie split up during the recording of their blockbuster 1977 album “Rumors,” which is one of the top-selling albums of all time. The group splintered in the mid-1980s and reunited for tours and/or albums several times, sometimes with all five members and sometimes not.

Curiously, the final split came after Buckingham and Christine McVie had released a 2017 duo album, and then the group performed as honorees of the 2018 MusiCares Person of the Year event in 2018. Buckingham was fired from the band and replaced by Crowded House’s Neil Finn and Tom Petty & the Heartbreakers guitarist Mike Campbell.