But judging by the raucous reception for their reunion on the final of The X Factor it was almost worth the wait.
The pair, who has sold more than 80 million records between them, belted out the original disco tune 100 degrees, a single from Kylie’s new Christmas album, Kylie Christmas.
They were joined by 10 male dancers in silver lurex shorts and Santa-themed capes.
“I’m actually going to start crying because I don’t think anyone understands how ICONIC this performance is,” tweeted one overwhelmed fan.
“I love Kylie and Dannii separately but together OMG. My glitter-o-meter just blew up,” wrote another.
Kylie, 47, and Dannii, 44, said they’d been saving a reunion like this for when it was “special and right”.
It was a special night for Wollongong wonder Cyrus Villanueva, 19, who fought back tears after his name was read out as the winner by host Luke Jacobz.
His fellow contestants and family stormed the stage to congratulate him on his epic victory.
“This whole experience has been unreal. I can’t thank everyone enough,” said Cyrus.
Cyrus’ mentor Chris Isaak showered the fan favourite with praise: “I’m so proud of him,” while his fellow judges also weighed in with lavish praise.
“You have something that moves people. It’s always a celebration in everyone’s hearts and souls,” said Dannii.
Cyrus took home a coveted recording contract with Sony Music. His new single Stone is out now on iTunes.
Worth the 30 year wait!