Queens Of The Stone Age's Josh Homme, Foo Fighters' Dave Grohl and Led Zeppelin's John Paul Jones are working together.
The trio are currently in a Los Angeles studio recording an album.
US website Antiquiet was first with confirmed news. They speak to Homme's wife, Brody Dalle of Spinnerette who says: "I'm not at liberty to talk about it… but I think it's is pretty fucking amazing.
"Just beats and sounds like you've never heard before."
The project has been in the pipeline for some time. Way back in 2005, Grohl told Mojo magazine: "The next project that I'm trying to initiate involves me on drums, Josh Homme on guitar, and John Paul Jones playing bass. That's the next album. That wouldn't suck."
This summer, Jones told a French reporter: "I'm working on some other music, which is more rock based, with a couple of other people. We hope to be everywhere this summer."
When pressed for more information, the bassist stalled: "It's a secret, actually. I shouldn't have even said that, you know? There are some exciting projects coming up, let's put it that way."