Fortunately, the Schools Secretary - who once inserted the phrase "post-neoclassical endogenous growth theory" into a Gordon Brown speech - did not describe the exact genre of music.
But a probing interview with the Department for Children, Schools and Families in-house magazine has revealed dark details. According to the publication, he recently bought the soundtrack of the blockbuster High School Musical. And he claims to know half the words to all the songs.
Mr Balls says the enthusiastic strains of teen heartthrob Zac Efron and the rest of the cast see him through car journeys. What his three children think of their father's singing, lord only knows.
You have to admire his frankness, though; most politicians would at least have tried to appear cool. Gordon Brown opted for The Beatles and Coldplay last year, and David Cameron boosted his "cool" factor by professing enjoyment of Bob Dylan and The Killers.
On another cheerful note, Mr Balls was recently spotted at Yarborough School in Lincoln, entertaining pupils with a juggling act.
The impressive display is sure to guarantee a handful of extra votes in the region's local elections.