Christine McVie

Without late bandmate Christine McVie, singer says, "We really can’t go any further with this."

Track comes from a new reissue, while Mick Fleetwood pays tribute to his late bandmate with a new cover.

Singer paid tribute to late bandmate with emotional rendition of "Landslide."

Fleetwood Mac drummer was joined by Sheryl Crow and Bonnie Raitt for a rendition of "Songbird."

"She was truly one-of-a-kind, special and talented beyond measure," the band wrote in a statement.

"We continue to hope for the best," she says.

There have been more than 40 of these outside projects, which deepen and add to the band's legacy.