Taylor Swift made a shock on stage announcement in Melbourne on Sunday evening, revealing a huge change for her upcoming Sydney shows.

The global megastar, 34, told the packed crowd she was revising her rule of never performing the same acoustic ‘Surprise Song’ more than once on her Eras Tour.

‘I want to be as creative as possible with the acoustic set moving forward and I don’t want to limit anything or say, “If I played this song, I can’t play it again”,’ Swift began

So, from now on, I don’t want to take any paint colours out of the paintbox or tools out of the toolbox.

‘I want to be able to play songs more than once if I feel like it and I want to be able to make changes to songs. Does that sound OK?’ she added.

Swift’s suggestion was met with huge applause from the roaring crowd.

Some of the acoustic Surprise Songs she has previously performed on her latest tour include Daylight, Red and Teardrops on my Guitar.

International Swifties vented on social media after Swift treated Melbourne fans to an extra special surprise song in the form of a mashup of her tracks Getaway Car, The Other Side of the Door and August.

‘WHAT POSSESSED HER TO DO THIS?’ exclaimed one fan on Twitter.

Another shared a meme of a stone-faced NFL player during a tickertape parade, along with the caption ‘The rest of the world watching Melbourne getting getaway car x august x the other side of the door mashup.’

Fans at Taylor’s first Melbourne Cricket Ground concert were also treated to a world-first announcement by the songstress that the special edition of The Tortured Poets Department would feature a new song called The Bolter.

With three shows slated for Melbourne this weekend, thousands of fans who missed out on tickets gathered outside the MCG singing and dancing to Swift’s hits.

The international trend has garnered the term ‘Taylor-gating,’ despite warnings from the MCG urging fans to only attend the venue if they have ticketholders.

Swift mania will soon hit Sydney with the pop star set to perform at four shows from Friday, February 23 to Monday February 26.