A couple of weeks ago, the Rolling Stones announced plans for a massive reissue of Goats Head Soup, their 1973 album. The new deluxe version of Goats Head Soup will feature all the things that you’d expect from a big album-reissue box set: Alternate versions, outtakes, a whole live album, a big book of essays and photos. It’ll also feature three previously unreleased Stones songs from the era. They’ve already shared “Criss Cross,” one of those songs. Today, they’ve dropped another one, and it features a fellow titan helping out on guitar.

“Scarlet,” the latest of the previously unreleased songs from the Goats Head Soup sessions, is a loose and sloppy blues-rock rambler, and it features Jimmy Page sitting in on guitar. This would be Page at or near his peak; Led Zeppelin released Houses Of The Holy a few months before the Stones released Goats Head Soup. Blind Faith’s Rick Grech plays bass.

In a press release, Keith Richards remembers this about “Scarlet”:

My recollection is we walked in at the end of a Zeppelin session. They were just leaving, and we were booked in next and I believe that Jimmy decided to stay. We weren’t actually cutting it as a track, it was basically for a demo, a demonstration, you know, just to get the feel of it, but it came out well, with a lineup like that, you know, we better use it.

Check it out below.

The deluxe Goats Head Soup reissue is out 9/4 on Interscope/Polydor/UMe.