Six Group One winners - another who promises to be and a few who probably should be. It's the formula for an intriguing Canterbury Stakes.

Headlined by the return of $20 million colt Zoustar, the race also boasts two of the country's best mares in Appearance and Red Tracer.

Frontrunner Rain Affair and Speediness have five Group One placings between them, while three-year-old Not Listenin'tome adds another dimension as the untapped talent.

It is little wonder trainer Chris Waller is cautious about the winning prospects of Zoustar in the Randwick feature.

"He's first-up over 1300 metres and it's going to be hard," Waller said.

"I haven't wanted to flatten him on the training tracks, I want to have a horse for the T J Smith.

"It's a juggling act. I'm banking on the horse's ability."

Zoustar has been defeated twice in eight starts, one of those coming at his first run in an otherwise dominant spring campaign.

Waller is mindful of that statistic heading into Saturday, and that the colt meets older horses for the first time.

Bookmakers believe the three-year-olds can overcome their seasoned rivals with Zoustar $2.75 in early markets ahead of Not Listenin'tome at $3.80.

The favourite's stablemate My Kingdom Of Fife is the outsider at $126 as he prepares to race for the first time in almost 2-1/2 years.

Waller compares him to Rangirangdoo and Metal Bender who made successful comebacks for the stable after long injury-enforced layoffs.

However, he doesn't expect that success to come on Saturday.

"Second-up in the George Ryder I expect him to finish about midfield and third up he should be ready to run a really good race," Waller said.

The trainer credited owner Richard Pegum's team for resurrecting My Kingdom Of Fife's career.

"It's been a team effort and it's taken plenty of time," he said.

"Mr Pegum's farm has done a tremendous job with him over a long period. They never let him get big and heavy which was the most important thing.

"They've sent me to him in great condition and with a clean pair of legs."