There wasn't room to swing a cat in the Birdcage.
Excitement in the exclusive Flemington enclosure rose a notch with the arrival of Good Charlotte rock brothers Joel and Benji Madden.
The duo squeezed their way into the Lavazza marquee on Tuesday, where people were pressed shoulder-to-shoulder for a glimpse of the stars served up for the Melbourne Cup carnival.
It was reminiscent of the chaotic crush surrounding last year's Melbourne Cup international celebrity, rapper Snoop Dogg.
Unlike the Dogg, who slid wordlessly into the marquee, the Good Charlotte boys stepped up to the podium for a chat.
Benji Madden admitted he didn't know a great deal about horse racing.
"I know that the horses move very fast and people bet a lot of money and lose a lot of money," he told reporters.
But Madden wasn't one of those people. He was later spotted celebrating ecstatically, having backed the Melbourne Cup winner, Shocking.
Another international performer, Irishman Ronan Keating, added to the celebrity hype in the lavish India-themed Emirates marquee.
Dressed in a dapper grey suit with white piping on his jacket lapels, Keating revealed he was no novice at the races.
"I have a couple of racehorses at home," he said.
Zara Phillips brought some royal kudos and her considerable equestrian expertise to the exclusive marquee.
The granddaughter of Queen Elizabeth and daughter of Princess Anne is an accomplished equestrian competitor, having won silver and gold at world championships in 2005 and 2006.
Ms Phillips, in a navy blue frock by US fashion house Thread Social, was laid back and keen to see some racing action.
"We primarily come to see the horses and have a good time," she said.
Elsewhere in the marquee, sports and television personalities sipped champagne, snacked on morsels of Indian food, and watched a posse of frenetic Bollywood dancers who were joined by former Australian Idol host James Mathison, delivering his own interpretation of Bollywood moves.
Olivia Newton-John appeared in the Myer marquee on the arm of her husband, John Easterling, and later sang the national anthem.
Former Olympic swimmer Michael Klim and his glamorous wife Lindy were marquee-hopping throughout the day, before heading to the Lavazza marquee where Lindy hit the DJ decks in the afternoon.
The former model and mother-of-two had taken lessons with DJ Grant Smillie.
"I sort of picked it up really quickly," she told AAP.
"We had some decks set up at home, and I practice and the kids dance."
Lindy soon had the packed marquee grooving to Salt 'n' Pepa's eighties hit, Push It.
Beyond the Birdcage, a crowd of about 100,000 revellers ensured there was no room at all for cat swinging at this horse race.