Guess who wins the rap battle.

Reebok recently hosted a workshop for young rappers in Manchester, England and surprised them with an appearance from Kendrick Lamar. In a new video, he watches the teens freestyle and eventually joins into the cipher himself. Lamar’s clearly excited throughout the entire video and delivers every line with an enormous smile. Watch the clip above and revisit our review of the recently one-year-old To Pimp A Butterfly. [via Stereogum]