Kathy O'Hara has been given a late autumn carnival opportunity with confirmation she will ride Estonian Princess in the Hawkesbury Guineas.

Estonian Princess will back up after winning the JHB Carr Stakes at Randwick on Saturday when Brenton Avdulla had the mount.

But with Avdulla riding the Anthony Cummings-trained Spy Decoder, Scott Aspery is hoping O'Hara's experience on Estonian Princess can help end the filly's autumn on a winning note.

"Kathy's won on the horse before and she knows her as well as anyone," Aspery said.

In a racing campaign that started in December, Estonian Princess has raced 10 times for three wins and two important placings in lucrative Magic Millions races, including the $1 million Guineas at the Gold Coast.

"She had two weeks off after the Gold Coast in January but aside from that she's been going for five months now," Aspery said.

Aspery said the spelling paddock would win out over a Queensland Guineas campaign.

"I think she has done enough," he said. "She deserves a break because she has proven she is worthy of a tilt at some of the better races in the spring."

Aspery has staying colt Star Wars also entered for the Guineas but the trainer said if he was to run on Saturday it would be against older horses in the Hawkesbury Gold Cup.

A failure on a heavy track in the Tulloch Stakes, Star Wars is being aimed at next month's Queensland Derby.

"He needs to have a run between now and Queensland and a mile race either at Hawkesbury or at Wyong on Thursday will be perfect," Aspery said.

Cup weights are headed by the Tony McEvoy-trained Mouro who has 59kg after winning the Rowley Mile at last year's corresponding meeting with 54kg.

Malavio, an Avdulla mount with 56kg, is the only other horse among the 16 entries to be weighted above the 54kg minimum.