Millar is a last-minute addition to the field at the world golf championships all-star HSBC Champions event at Sheshan International Golf Club as a reward for his superb 2015-16 summer.

It means the unheralded world No. 398 will join the game's biggest names and 43 of the world's top 50 for a shot at glory in Shanghai.

The invite comes with a chance to share in the prize money, with no cut after the first two rounds and the winner to pocket almost $2 million.

To put the opportunity in context, the HSBC Champions event is worth 10 times as much as the Australian Open, while Millar will play in the Queensland Open on Thursday in front of a handful of fans and battle with 132 players for a share of $110,000.

Millar thought his hopes of playing in the lucrative tournament were dashed when he finished third on the Australian Order of Merit last year.

He was elevated to first reserve in the 78-man field on Tuesday and sealed his spot when English golfer Andy Sullivan withdrew.

It will be one of the biggest tournaments Millar has played in and could be the perfect boost for his bid to win the Japan Tour qualifying school event to earn a tour card.

Millar, who coaches at Gold Creek Country Club, knows his chances of winning against the likes of major championship-winners Rory McIlroy, Adam Scott and Henrik Stenson are slim.

"But if you're not in the field, you can't beat them. It doesn't mean you can't win, but guys like Dustin Johnson, McIlroy, Stenson ... they'll be damn hard to beat," Millar said.

"No one pulls out of these sort of events so when I was first reserve I thought I was just going to miss out, but I'm pretty excited by the opportunity.

"You're realistic about your chances, especially with the quality of players that you're sharing the locker room with.

"This is what you want to play for, you want to play in the best fields and try to compete. If you do well, it's a great feather in your cap.

"I haven't had an awesome opportunity like this one since I qualified for the British Open in 2011."

Millar was named player of the Australian tour last year, securing 11 top-10 finishes and winning his first tournament – the New Zealand PGA.

However, he fell agonisingly short of a top-two Order of Merit finish, which would have guaranteed him a start at the HSBC Champions event.

Millar played at the Dunhill Links Championship at St Andrews two weeks ago and when he arrived home, he had to scramble to get a Chinese visa in case he was called into the world golf championship field.

The visa arrived on Wednesday morning and Millar will fly from Brisbane to Canberra on Sunday night before flying to Shanghai for a massive opportunity.

"There's a good chance you could come up and play with the big guys ... I've played with some big names before so you're a little bit unsure of what to expect," Millar said.

"But all of them have been great people to play with. Yeah, they do some things differently but they also do things you're capable of."

Millar will return to Australia after playing in China to prepare for the NSW Open and the Australian Open.

He will skip the Australian PGA Championships this year to focus on Japan qualifying school in a bid to earn his tour card.