The Melbourne Racing Club will renovate "the Heath" after the Caulfield Cup is run, and has made the very popular decision to let racegoers party on the turf during Brown's set, at the close of the week-long cup carnival.

The Mentone born sensation – who recently, along with that other Australian hot-as-Hades rapper Iggy Azalea, and Sydney boy band 5 Seconds of Summer, was  nominated for a MTV Europe Music Award – will be the VRC special guest at the Caulfield Cup and she will be flying the flag for Australian designers.

The We Run the Night singer will be dressed by Manning Cartel with headwear  designed by the ever talented Victoria Novak.

Brown said she was looking forward to the crowd letting loose after the day's formal festivities.

"[The Melbourne Racing Club] haven't really done anything like this before and I'm so excited," she said. "People spend a lot of time getting ready for the races, getting all dolled up, matching their shoes and hats and everyone really gets into the day. So it's going to be great to really kick on after the last race and I am so happy to be able to perform. It is also the best excuse for the ladies to kick off their heels after the long day."

Manning Cartel - hat by Victoria Novak

Brown – who lives most of the year in Los Angeles – said she was thrilled with the international success of Australian artists, such as Azalea and 5 Seconds of Summer – who are  contenders to rival One Direction with screaming teenage fans.

"It's a dream for every Australian artist to be able to go out in the world and get the work and be recognised," she said. "Aussie artists are really making a break for it and going for it right now and it's awesome."

It was a "dream" to be able to perform in her hometown.

"I try and get back [to Australia] every few months, I'm always doing shows here and it's good for my mentality," she said.

"I love the Australian culture, the way we live our lives, we are so lucky  and we don't really know it, but that's cool. We are a very real country."

The Melbourne Racing Club is expecting a sell-out crowd at the Caulfield Cup and the weather looks like it will play its part, with a mainly sunny morning forecast with patchy high cloud during the afternoon and a welcome high of 26 degrees.

Fewer than 3000 general admission tickets were left for sale on Friday with final crowd numbers expected to be north of 30,000.

The marquee day of the Cup carnival, celebrities are expected in their numbers in the Heath enclosure, Caulfield's answer to Flemington's feted Birdcage.

At the David Jones Art Nouveau-inspired tent ambassadors Jessica Gomes, Jason Dundas, Montana Cox and Emma Freedman will play host to Tom and Hoda Waterhouse, David Jones CEO Iain Nairn, David Jones designers Carla Zampatti, Bianca Spender, Ginger & Smart designers Genevieve and Alexandra Smart, Marc Freeman, Josh Goot as well as football power couples, Carlton's Chris and Rebecca Judd and Marc Murphy and Jessie Habermann, as well as dual former Miss Universe Australia's Scherri Lee Biggs and  Rachael Finch.

The Crown Golden Ale marquee will play host to actress Jessica Marais and partner James Stewart, horse trainers Peter Moody and David Hayes, actor Vince Colosimo, snowboarder Alex "Chumpy" Pullin, and Dancing With the Stars judge Adam Garcia.

Australia's Got Talent winner Bonnie Anderson will belt out the national anthem before the big race and with Sydney-based DJs The Faders set to perform at the after party.

The white rose is the day's traditional flower which works especially well with this year's hottest race wear trend, white on white.

The Chadstone Fashion Stakes has upped the ante this year with a hefty prize for the eventual overall winner of the fashions on the field competition of Royal Ascot 2015 Tour valued at $19,000 for two people including flights to the hallowed turf track.

Registration for the four categories – Classic Kids, Stylish Ladies 18-40 years and 40+ years and Stylish Gentlemen – opens at 10.30am in the entertainment and fashion precinct.

More than $100,000 in prizes are up for grabs.

Judged by a panel of fashion, media and celebrity identities, including racing blueblood Emma Freedman, entrants will be marked on their overall outfit, accessories and attention to detail, seasonal appropriateness and deportment.

Gates open at 11am.