Sia - 'This Is Acting' - Hitmaker-for-hire makes a silk purse out of songs rejected by Rihanna, Adele and others

Camera-shy Australian Sia occupies a singular position as a hit pop songwriter who moonlights as a chart-topping artist in her own right. ‘This Is Acting’ features tracks she wrote for A-listers including Adele, Beyoncé and Rihanna but kept for herself after they were rejected. It’s an album filled with scraps, then – but they’re scraps that would be snapped up by most pop stars in a second.

Any faults can be rebutted, at least partly, by the album’s conceit. Some of the songs don’t feel especially personal, but they weren’t supposed to be. Sometimes she relies on unimaginative imagery like “a house on fire” and “footprints in the sand”, but when you’re aiming to create global mega-hits like Rihanna’s ‘Diamonds’ and David Guetta’s ‘Titanium’ – both Sia’s handiwork – it’s best not to complicate things. It’s a bit strange when Sia apes Shakira’s vocal style on ‘Move Your Body’, but it’s also entirely possible she penned this tune with the Colombian in mind.

Despite these niggles, the album is fairly cohesive. ‘Move Your Body’ is pure Europop and ‘Sweet Design’ is a clattering R&B track. Elsewhere it features the bombastic balladry of her last album ‘1000 Forms Of Fear’.

But her songwriting sparkles – ‘Alive’ rivals her 2014 hit ‘Chandelier’ for sheer drama. ‘One Million Bullets’ and ‘Unstoppable’ boast infectious pop melodies and ‘Cheap Thrills’ benefits from some silly but irresistible playground chant hooks. Even the plodding ‘Broken Glass’ wins you over with its gloriously cheesy key changes.

Despite recently saying she “doesn’t care” about the Kanye-produced soul-pop jam ‘Reaper’, her vocals are committed throughout. When she strains so hard on ‘Alive’ that her voice becomes pretty ragged, it’s thrilling. If you can buy into its concept, Sia’s play-acting is very entertaining indeed.