When tame stars turn wild – Minogue, Cyrus, Bieber – it’s generally a tightly PR’d plot to shed a teen-friendly, butter-wouldn’t-melt image that is showing diminishing returns and to shock their way into more dependable adult wallets. So the recent transformation of Newcastle’s Beth Jeans Houghton, from psych folk cyber-Florence into confrontational garage rocker Du Blonde, could easily be a Miley Cyrus parody. On the cover of second album Welcome Back to Milk, then, she’s pictured naked bar shaggy white coat, trainers and merkin, eschewing airbrush and nipple tape and resembling a drunk punk yeti on a nudist fun run. Launching this grubby pub gig with a rumbling Kills clatter called If You’re Legal (“my boy is going down”), her lyrics have clearly turned as filthy as her guitars. She seems, at first glance, an art satire on pop’s sex-trade cynicism.

Not so. Houghton has consistently metamorphosed since emerging in 2008, and Du Blonde is the genuine result of a 2012 breakdown and a creative epiphany at the David Bowie Is exhibition. She aspires to the supernatural enigma of the art pop chameleon and Du Blonde is an authentic mutation, swapping sellable witchy theatrics for credible rock grit. Guided by producer Jim Sclavunos of the Bad Seeds, she exorcises her psychological and emotional traumas on Hard to Please and Raw Honey with a soulful grunge punch. They even screw up a cover of Pixies’ Where Is My Mind?.

There’s no doubting her commitment. Unfortunately, dressed down, muttering meekly and avoiding the saucier songs about Dr Jekyll fellating Mr Hyde, she fails to exude the charisma of an alien encounter tonight. Du Blonde indulges as much in boorish blues rock and 70s prog as Sparks, the Cramps and early PJ Harvey, and Houghton remains at her best when stripped back to her folk gospel roots on ballads After the Show and Isn’t It Wild. Not wild enough, Beth…

• At the Shacklewell Arms, London, 3 August; and Moseley Folk festival, 4 September. Then touring until 10 October.