Miller-Heidke sang the screen-role of Amber in the world premiere of Michel van der Aa's opera "Sunken Garden" for the ENO in April 2013. In September the singer-songwriter left Sony Records, which she described as a "corporate juggernaut." She started work on her fourth Australian studio album, "O Vertigo!" (14 March 2014), and sought crowd-funding via PledgeMusic to record it independently, as well as donations for the protection of the Great Barrier Reef. She broke the record on Pledge for the fastest target achievement: in three days the album was paid for and donations for the reef continued. "O Vertigo!" was produced by John Castle for UK-based label Cooking Vinyl and reached No. 4 on the ARIA Albums Chart. It was also nominated for the ARIA Award for Best Adult Contemporary Album in 2014.