Teddy bears adorn the stage and bizarrely shaped, loopy neon lights resembling cartoon trees offer the promise of a rather surreal performance.

And when Sia and her crew bounce onto stage dressed in black with their features marked as big, smiley fluorescent strokes on their outfits the promise seems fulfilled.

But as soon as the diminutive Australian opens her mouth, what she is wearing is the last thing anyone is thinking about.

It is hard to believe that the tiny blonde, who quickly discards the neon smiley suit for a rather fetching pair of striped, cropped dungarees, could possibly be creating such a powerfully emotional sound.

But she fills the room with her voice, painting every inch of it with gorgeous melody.

Sia, best known as the silken voice of Zero 7, is something of an enigma as a performer.

She sings with absolute confidence - with searingly poignant yet uplifting bittersweet melodies.

But she is also happy to chat and joke with the crowd and seems completely unaware of how immensely moving the beautiful musical soundscape she creates is.

As well as her own material, Sia treats the crowd to a few Zero 7 classics along with the spine-tinglingly beautiful Breathe Me, used in the soundtrack to the finale of Six Feet Under.

It seems strange to be listening to such soul-searching tunes, best suited to a jazz club, or a chilled out Sunday morning, in the sweaty confines of the Zodiac room.

But her ready humour and capricious emotions are infectious. And the crowd swayed along, carried away in Sia's musical journey.

Sia was brought to tears reading aloud a note thrown to her from a fan, who told of how her mother, also a Sia fan, tragically died of cancer.

But the next minute the songstress is up and joking again about how unfair it is to make paying customers "beg for more" in an encore before promising she would be providing the crowd with a "climax".

It was a stunningly beautiful set which could seem a tad depressing if it wasn't imbued with so much gentle humour, and a sense of underlying hope and happiness.

The crowd left mellow - but happy.