Eurovision superfan Mel Giedroyc and the victor of the Eurovision Song Contest 2015, Mans Zelmerlow, host live from MediaCityUK in Salford as the show comes from the north west of England for the very first time.
The electronic duo Electric Fields came second place with 114 points with their song 2000 and Whatever.
Will Kate Miller-Heidke follow the Eurovision path trodden by Guy Sebastian and Dami Im, or could another Australian music act steal the show?
The singer-songwriter and actress won with 87 points in the popular vote and 48 points from the judges, giving her 135 points overall.
' Thanks to everyone who voted, and to all the other artists who provided such a brilliant, eclectic and stiff competition.
She said she experienced a bout of nerves before she performed the winning song dressed in a towering metres-long silver dress and headpiece.
Kate Miller-Heidke performs Zero Gravity on Saturday. I've had a ball, and I'm so grateful and thrilled that I get to represent Australia at Eurovision'.
Paul Clarke, the creative director of Eurovision - Australia Decides, describedMiller-Heidke's victory as "a win for out-of-the-box brilliance, which Eurovision devours".
Co-written with her husband Keir Nuttall, Kate Miller-Heidke's song Zero Gravity explores the singer's experience with post-natal depression, which she suffered after the birth of her son, Ernie, in 2016.
The Eurovision Song Contest will be held in Tel Aviv, Israel in May.
Miller-Heidke's performance was defined by an absolute belter of an operatic note, but her dramatic aerial staging - which saw a swaying dancer hoisted metres off the ground - may have helped, too. Kate is a total original and Eurovision will love her.
The contest was won by Israeli singer Netta with her song Toy which had the message of encouraging people to celebrate their differences.
Fans said they feel the song could be a victor at Eurovision in May.