Defending titleholder I'm A Rippa is regarded by many as Tony Gollan's second stringer in the Group Three George Moore Stakes but the trainer has warned punters not to take him lightly.

I'm A Rippa, who has earned $1.2 million prize money, will be joined by stablemates Outback Barbie, the favourite, and Natch in Saturday's 1200m-race at Doomben.

Gollan is aiming to win the George Moore for the fourth time in five years after taking the race with Didntcostalot (2015), Most Important (2016) and I'm A Rippa.

Outback Barbie and I'm A Rippa resumed in the Listed Keith Noud Quality three weeks ago with Outback Barbie winning and I'm A Rippa third.

Natch resumed with a seventh in an unsuitable 1000m-race at the Sunshine Coast.

I'm A Rippa meets Outback Barbie 2kg better and has drawn barrier three while the mare has barrier 13.

Gollan believes both will race well and refused to nominate one a better chance than the other.

Outback Barbie and I'm A Rippa worked on the course proper at Doomben on Tuesday and pleased Gollan.

I'm A Rippa led out but Outback Barbie joined him in the straight with the pair working strongly to the line together.

"I expect this to be a high pressure race early. It is no secret I'm A Rippa will go forward and be on the pace," Gollan said.

"From barrier three he can roll along and I think he will be a hard nut to crack.

"I'm A Rippa has a much better win rate second-up and he is down a bit in weight."

Gollan also expects Outback Barbie to roll forward from her wide barrier.

"She has been dogged by wide barriers her whole career. But there looks to be so much pace in this race, by going forward hopefully we can get cover in behind the speed," he said.

"She put them away quickly in the Keith Noud when she was able to get cover.

"Outback Barbie is showing the benefit of a long spell after the winter. She has really matured and turned into a lovely mare."

Gollan said both Outback Barbie and I'm A Rippa would have their grand finals on Magic Millions day (January 11) but their exact races were still to be decided.

Both are likely to contest the new Gateway race at Eagle Farm on December 14 for automatic entry to the Group One Stradbroke Handicap next year.

Gollan said Natch had also come along nicely after his first-up run and had a good second-up record.