Undiscovered for decades, here is the full 33-minute version of Isaac Hayes’s psychedelic jam Do Your Thing.

For years – decades – the ‘long’ version of this trippy Isaac Hayes jam came to a juddering halt after nearly 20 minutes of glorious, grooving funk and soul with the jarring sound of a needle scratching violently across a piece of vinyl.

Turns out there’s another 13 minutes and, having only recently been rediscovered on the original master tapes, the rest of the tune has been put back together.

The added section is extraordinary: somewhere in between free jazz and psychedelic rock, it’s unlike even the most out-there examples of psychedelic soul.

Hayes was already a cutting edge funkmaster at Stax when he agreed to create a soundtrack for the film Shaft in 1971, breaking the convention that R&B songs routinely timed out around the three-minute mark.

He’d been breaking new ground since 1969 when he released his landmark Hot Buttered Soul – an album comprising only four tracks. He followed that with a pair of 12-minute extravaganzas on The Isaac Hayes Movement and went even further with a 15-minute track on …To Be Continued.

Do Your Thing, taking up most of the fourth side of the Shaft soundtrack (a double-LP) would be his longest tune yet, even if nearly half of it lay undiscovered in the vaults for decades.

The musicians backing Hayes (vocals & keyboards) are the Stax house band The Bar-Kays, a group who learned their trade in Memphis from Booker T & The MGs and paid their dues with Otis Redding (four of them liteally paid with their lives in the same plane crash):

Charles Pitts & Michael Toles on guitars; Lester Snell on electric piano; James Alexander on bass; Willie “Too Big” Hall on drums; Gary Jones on congas & bongos; Richard “Johnny” Davis on trumpet; John Fonville on flute; and Pat Lewis, Rose Williams & Telma Hopkins on background vocals.

Telma would go on to be one of the girls in Dawn (aka Tony Orlando & Dawn), singing hits like Tie A Yellow Ribbon, while the legendary Willie Hall appeared in both Blues Brothers movies.