Although Daniel Johnston is feted by musicians, few of us have directly experienced the singer-songwriter, who suffers from bipolar disorder. But when Spiritualized's Jason Pierce was offered the chance to curate Newcastle's week-long Evolution festival, Johnston's was the first name on his team sheet.

With Pierce in the audience, Johnston shuffles to the stage with tiny "Excuse me, sir"s, his plaintive, childlike voice emerging from a great teddy-bear-like body. Reading lyrics from a book, his acoustic guitar resting on his big belly, the 43-year-old Texan plays the instrument as if he's scraping it to remove a stain.

His lyrical concerns are harrowing and beautiful: "Love will haunt you like a ghost ... It could all end next week." While people in the audience compare him in whispers to the bluesman Robert Johnson, there's something uncomfortable about cheering someone whose troubles are so apparent. However, this is tempered by his delight in the applause and his cheeky, blackly humorous playing to the crowd.

He thanks "London", and tells a dry, oft-trotted out anecdote about his dream in which "a man was sentenced to death for attempting to commit suicide". A song that begins "Baby, you're driving me crazy" is mischievously ironic, but it's difficult not to be disturbed by a line like, "He was smiling through his own personal hell."

Johnston's awkward delivery is an acquired taste, but it becomes increasingly obvious that he is the conduit for some of the finest, most insightful songs being written. Every emotion possible intensifies as he switches to piano, and by the time he blasts into an astonishingly pure True Love Will Find You in the End it's difficult to know whether to cry or whoop. For once, the myth is equalled by the man.