Mos Def joined Kendrick Lamar on stage at Osheaga.
With Action Bronson pulling out of Montreal's Osheaga festival, Mos Def (who now goes by Yasiin Bey) was brought in to replace him. Not only were Canadian fans treated to a rare performance from the rapper, but he also made an appearance during Kendrick Lamar's set, helping him out on his To Pimp A Butterfly single, "Alright," replacing Pharrell on the hook.
Reports from the scene also quoted Kendrick as saying that Mos Def inspired him to rap, so it was probably as big a moment for him as it was for the crowd. Perhaps there'll be a collaboration down the line?