The Entourage actor was reportedly meant to be appearing in the Lavazza marquee and the Emirates tent at the event, but cancelled the Emirates appearance at the last minute when Lavazza offered him more money to remain in their area.
A spokesperson for Emirates told the Sydney Morning Herald: "He committed to us first... we'd been in discussions for weeks, even months. We'd organised car transfers and special arrangements then at 10pm last night we received an email saying he's received an offer too good to refuse. It's poor form."
Grenier, however, revealed earlier today that he was enjoying the races despite being criticised by the organisers. "I think there's going to be too much collective fun had by all," he said. "I like to have a good time. I like to dance. I also like to play chess at home, but tonight I think we'll skip the chess and go straight for the dancing.
"I absolutely love horse racing and I'm looking forward to placing a couple of bets and looking forward more to winning. I'm very serious... if there's the right job, I would love to spend a couple of months in Australia. Hopefully somebody will take my offer and invite me here."
Dannii Minogue's partner Kris Smith was also there with father Eddie and old friend Gary, who had both flown over from England for the event. Smith revealed that Minogue was spending the day with his mum and their 16-month-old son Ethan, saying: "[They've] taken him to a barbecue at a friend's house to watch the race."
Sarah Jessica Parker recently revealed that she is "excited" to attend Oaks Day on Thursday. Kim Kardashian is also believed to still be turning up as a special guest at the racing carnival at some point despite announcing her split from husband of 72 days Kris Humphries yesterday.