Fan of Macklemore & Ryan Lewis? Erm, what exactly does Ryan Lewis do?

Macklemore and Ryan Lewis' The Heist was one of the breakout albums of 2013, thanks to the hit single Thrift Shop.

But that album spawned a question that has been plaguing many fans: What exactly does Ryan Lewis do?

You know, that guy who's always hanging out on stage when Macklemore is rapping.

TV talkshow host Jimmy Fallon understood fans' plight and sought to answer the question on The Tonight Show  - with the help of Ryan Lewis himself.

He went out on the streets asking clueless fans the question - and most of them did not even realise they were talking to the producer.

Watch the video above for the answer - and a cameo appearance from someone more famous than Ryan Lewis.

Source: YouTube