The Foo Fighters brought out a special guest over the weekend to pay tribute to Sinéad O'Connor.

During an appearance at Japan's Fuji Rock Festival, Alanis Morissette joined the band to perform O'Connor's 1987 single, "Mandinka."

The Irish singer died last week after being found unresponsive at a home in London. She was 56.

No cause of death has been released, but London police have said it was not being treated as suspicious.

At the festival, Foo Fighter's frontman Dave Grohl announced, "We're singing this song for a reason tonight."

"Yes, for a beautiful woman with high intelligence and deep empathy, way ahead of her time, who is no longer with us," Morissette added. "This is for her."

It's just one of many expressions of grief and tribute to O'Connor.

Singers Pink and Brandi Carlile performed a cover of O'Connor's hit "Nothing Compares 2 You," (which was written and composed by Prince) during Pink's concert in Cincinnati after O'Connor's death was announced.