Last week, Run The Jewels debuted the Boots-produced “Meowrly,” the surprisingly listenable first song from their gloriously bonkers Meow The Jewels remix project. They assembled an impressive lineup of big-name talent to help out with cat noise-wrangling, including Portishead’s Geoff Barrow, Zola Jesus, Baauer, the Alchemist, and Dan The Automator, and now El-P has announced that trip-hop legends Massive Attack — who were seen in the recording studio with RTJ earlier this year — will also be contributing a track. El-P tweeted that they’re still working out an official release date, but the plan is to have it out by September. The digital version will be released for free, and all proceeds from vinyl purchases of the album will go to victims of police brutality.

ALERT: WE HAVE JUST RECEIVED THE MEOWMIXXX BY @MassiveAttackUK AND IT IS FUCKING CRAZY!!!!!

— el-p (@therealelp) July 23, 2015

#MeowTheJewels is being made strictly to put money in hands of people in need. huge shout to all the amazing producers contributing. <3

— el-p (@therealelp) July 23, 2015

#MeowTheJewels will be released to everyone for free as well as on limited deluxe edition vinyl.

— el-p (@therealelp) July 23, 2015

%100 of all profit of #MeowTheJewels will go to charity.

— el-p (@therealelp) July 23, 2015

.@yarthox yes it will be available on streaming services.

— el-p (@therealelp) July 23, 2015

.@dmcconnell87 of course. each piece of vinyl has a flattened kitten inside it.

— el-p (@therealelp) July 23, 2015

as for when it is dropping, we will be announcing an exact date very soon but if all goes right it drops in september.

— el-p (@therealelp) July 23, 2015