Silent Achiever will try to make it three successive Group One weight-for-age wins in Sydney with trainer Roger James confirming she will run in the Queen Elizabeth Stakes.
The New Zealand mare was also entered for the Sydney Cup but the prospect of another wet track at Randwick on Saturday was a determining factor.
James said it would not be fair to run her over 3200 metres in the Cup on a heavy surface so the decision was made to aim at the shorter Queen Elizabeth (2000m).
The $4 million Queen Elizabeth is worth four times as much as the $1 million Sydney Cup but James says that is not the main consideration.
"The 3200 metres on a wet track could be too taxing," James said.
"But the Queen Elizabeth is going to be a very hard race. She tried to win it last year coming back from the 2400 metres of the BMW and didn't.
"And there will be some new horses like the ones coming out of the Doncaster for the Queen Elizabeth which makes it even harder."
Silent Achiever finished a close second to three-year-old Fiveandahalfstar in the 2013 BMW then ran fourth in the Queen Elizabeth.
But the addition of blinkers this autumn has been a master stroke with the mare unbeaten in four starts, three at Group One level including the Ranvet and BMW.
Nash Rawiller has chosen to ride her in the Queen Elizabeth over Royal Descent, second in the Doncaster as part of a Chris Waller-trained first four.
Doncaster winner Sacred Falls, fourth placed Hawkspur and 2011 Queen Elizabeth winner My Kingdom Of Fife are Waller's likely runners.
The trainer said third placed Weary would not run having performed beyond expectations in his first Australian campaign since coming from France.
"I don't think he's a weight-for-age horse yet," Waller said.
Heading the market is a horse owned by the Queen for whom the race is named.
Silent Achiever nabbed Carlton House in the Ranvet to win by a half head and is the second favourite.