The former Guns N' Roses guitarist, who is currently working on a solo LP, revealed the news on his Twitter account last night. In the post, he said that Grohl performs drums on the track and former bandmate McKagan plays bass.
"Great jamming w/Duff & Grohl tonight, the track is a killer instrumental, very heavy," he wrote.
Slash's solo album - expected to be called Slash & Friends - is expected to be released in early 2010.
The record already features a number of guest collaborations, including Iggy Pop, Nick Oliveri, Ronnie Wood, Flea, Jason Bonham, Fergie and Maroon 5 singer Adam Levine.