Yasiin Bey, formerly known as Mos Def, joined Kendrick Lamar on stage at Montreal’s Osheaga festival –Saturday (Aug 1).

Not only were Canadian fans treated to a rare performance from Yasiin Bey, but he also made an appearance during Kendrick Lamar’s set, performing a special version of the To Pimp A Butterfly single “Alright,” replacing Pharrell Williams on the hook and spitting a freestyle.

Kendrick reportedly told the audience that Mos Def was the reason he began rapping — making the surprise performance just as special to the Compton MC.

Perhaps there will be a collaboration down the line? Check out the performance below.

(Source: PAP)