The 'Lightning Bolt' singer may be famous for his folk styling and acoustic tracks, but he is impressed by '13', the heavy metal legends' first album with original singer Ozzy Osbourne in 37 years.
He said: ''The new album is great. It's not, 'Wow it's amazing' - it's not got the songs that are like the classic Sabbath songs - but it is surprisingly good considering they haven't made a record for so long. ''People think I say that just because they were in recording with [producer] Rick Rubin before me, but that's not true. I really like that album. I haven't seen them live, but I have heard they're meant to be really good.''
Jack, 19, also said the location he's been most blown away by since releasing his self-titled debut album and visiting different parts of the world has been Japan.
He added to NME magazine: ''That's had the most impact on me out of all the places I've been. It was weird there, but they appreciate my songs, written about my little town. I'm just singing about observations really, yet they can appreciate it. Half of them can't even speak English. It's crazy, it really baffles me.''