Zendaya made an unannounced appearance at Coachella on Saturday, joining Labrinth for a surprise duet during his set. As Variety reported, the "Euphoria" star emerged near the end of Labrinth's performance of “I’m Tired” to deliver her vocals on their collab. [readmore label="READ MORE: " link="https://etcanada.com/news/968204/zendaya-fangirls-over-rihannas-super-bowl-performance-with-lip-sync-battle-reference/"] She then stuck around to join him for “All of…