Melbourne has overtaken Sydney as Australia's most populous city for the first time since the 19th Century gold rush, following a boundary change.
Sydney has proudly held the title for more than 100 years.
But with populations rapidly growing on Melbourne's fringe, the city limits have been expanded to include the area of Melton.
The latest government figures, from June 2021, put Melbourne's population at 4,875,400 - 18,700 more than Sydney.
The Australian Bureau of Statistics (ABS) defines a city's "significant urban area", by including all connecting suburbs with more than 10,000 people.
"With the amalgamation of Melton into Melbourne in the latest... classification, Melbourne has more people than Sydney - and has had since 2018, " the ABS's Andrew Howe told the Sydney Morning Herald newspaper - which described the redrawn boundary as "a technicality".
Proud Sydneysiders will point to the ABS's conclusion that when looking at the greater Sydney and Melbourne regions, Sydney remained bigger in June 2021.
Greater regions of a city take into account its "functional area", the ABS says, and include populations who frequent or work within the city, but may live in small towns and rural areas surrounding it.
However the federal government predicts Greater Melbourne will overtake Greater Sydney in 2031-32.
Melbourne's rapid growth is largely thanks to international migration, Australian National University demographer Liz Allen told the BBC.
Dr Allen noted that unlike Sydney, which has a "historical hangover" of a time when "it didn't want to be seen as anything other than white", Melbourne has a reputation for celebrating diversity.
It is also an attractive migration destination as it has employment and education opportunities comparable to Sydney, but has historically been more affordable than the harbour-side city.
It's not the first time Melbourne has held the title of Australia's biggest city.
As a result of the gold rush in the late 19th Century, which saw migrants flock to the state of the Victoria, Melbourne grew rapidly and outnumbered Sydney until 1905.