James Hetfield has named Ronnie James Dio as the greatest rock vocalist of all time, praising the late singer’s natural ability, powerful range and lasting influence on Metallica. The choice highlights Dio’s importance to heavy metal, despite Hetfield’s broad musical tastes and admiration for vocalists across genres.

Dio fronted Rainbow and Black Sabbath and died in 2010; Metallica later honoured him with the nine-minute ‘Ronnie Rising Medley’ on the 2014 tribute album *This Is Your Life*. Hetfield said Dio’s 1970s blues-based hard rock is embedded in Metallica’s musical DNA, and recalled being surprised by Dio’s simple advice for protecting his voice: a small glass of wine before singing.