There was a “duets” album that came out with a lot of guest stars (some of whom are now deceased) a few years ago.
http://www.youtube.com/playlist?list=PL-op_9uvotoRY8VgOP20R9ENeoavcarml
I’m Back! Family & Friends
by Sly Stone - Topic
14 videos
Dance To The Music (feat. Ray Manzarek)
Everyday People (feat. Ann Wilson)
Family Affair
Stand!
Thank You (Falettinme Be Mice Elf Agin) (feat. Johnny Winter)
[I Want To Take You] Higher (feat. Jeff Beck)
Hot Fun In The Summertime (feat. Bootsy Collins)
Dance To The Music (Extended Mix)
Plain Jane
His Eye Is On The Sparrow
Get Away
Dance To The Music (Club Mix)
Family Affair (Dubstep Mix)
Thank You (Falettinme Be Mice Elf Agin) (Electro Club Mix)
"The Washington Post's Allison Stewart was also unfavourable towards the release, stating that "Stone seems more like a visitor to these tracks, like somebody assembled them and he showed up sometimes. He sounds tired."[6]