Lindsey Buckingham has written a tribute to “a friend, a soul mate, a sister,” Christine McVie, his longtime Fleetwood Mac collaborator who died earlier this week at the age of 79.

“Christine McVie’s sudden passing is profoundly heartbreaking,” he wrote in a social media statement. “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.”

Check out his handwritten note below. Buckingham and McVie last worked together in 2017 on the collaborative album Lindsey Buckingham / Christine McVie, at which time the pair embarked on a wide-ranging tour.

Following McVie’s passing, tributes poured in from around the world of music and entertainment, including from Fleetwood Mac’s Stevie Nicks, who wrote “See you on the other side, my love,” and from Mick Fleetwood, who said, “Part of my heart has flown away today. I will miss everything abut you.” Check out a comprehensive roundup of tributes.