For more than 25 years, DOOM (a/k/a MF DOOM) has been one of Hip-Hop’s hardest MCs to pin down. The British-born lyricist has historically swapped out names, reinvented himself with a masked face, and retreated to tropical islands for years on end. However, when the Operation Doomsday creator makes an appearance or a song, he almost always makes it count.

DOOM performed at March’s 2016 South By Southwest festival. Not there in the flesh, the former KMD front-man transmitted via video for a highly engaged audience, as part of a DOOMstarks set with Ghostface Killah. At the time, Heads tripped over an alternate “Retarded Fren” mix that emerged from that concert set. However, it appears that one show-goer caught something apparently even more grabbing.

During the set, DOOM pushed the button on his collaboration with Jay Electronica, who was also not in attendance. Never before played live, the moment was captured on camera. The song title remains unknown. However the collabo is clearly deliberate, as Jay Electronica shouts out his rhyme partner in his breathless verse. MF DOOM shared the video on his Facebook page.

Like DOOM, Jay is someone who can be sparse with output one minute, and quite prolific the next. Both artists who regularly move about the world are each MCs who also are renowned producers, and MCs to carry ties to Yasiin Bey, Nas, and PRhyme.

Previously, DOOM has collaborated with other elusive Hip-Hop artists including Kool Keith, Madlib, and C-Rayz Walz. Just yesterday (5/13), Jay Electronica appeared on Chance The Rapper’s The Coloring Book mixtape.

Click here for the video.