In a pleasant surprise, Bonjoy’s breakout campaign has been extended.

Thoughts of going for a break and getting prepped for a Group 1 assault at the end of the year has been put on hold for another week.

It was thought that Bonjoy was in the paddock after missing the Detonator Stakes (1800m) with a foot abscess, but trainer Jason Miller says it's all systems go for Saturday's Listed Sheila Gwynne Classic (1400m) at Ascot.

"She's sound as a bell and so well within herself," Miller said.

"She's been going good for a long time, but this is her final run before a spell.

"It will give her three months in the paddock which has worked out well, timing wise.

"She's also just had the four runs this time in, so she's hasn't been overtaxed or had hard runs.

"I think it's worked out good."

Bonjoy has fashioned a sharp record at Ascot since November and is on a hot winning streak of three consecutive races.

She's quickly established herself as a key Ascot carnival contender after winning the Listed Starstruck Classic (1600m) and two $100,000 races: the Celebration Of Life Day Trophy (1500m) and the Ascot Mile (1600m).

Improving an already impressive strike rate was denied after she was a barrier scratching in the Jungle Mist Classic (1200m) and feet issues kept her out of the La Trice Classic (1800m) and Detonator Stakes (1800m).

Bonjoy carries the 58.5kg topweight in the Sheila Gwynne Classic and will have regular rider, Clint Johnston-Porter as her companion.

In a field of 10 starters, they combine from barrier five.

Despite missing a key lead up race and a 39-day gap between runs, Miller says he hasn't increased Bonjoy's workload leading in.

"I've actually backed off her work," Miller said.

"She's already got the residual fitness.

"She'll have some freshness in her legs."

Bonjoy's elevation and the turn of foot she's shown in the past five months has given Miller confidence she can reach Group 1 heights in the Railway Stakes at Ascot carnival time.

Early going he rated her ahead of stable mate Admiration Express, who almost caused a boil over when runner-up to Light Infantry Man in last December's Group 1 Northerly Stakes (1800m).

If there is going to be a threat to Bonjoy in the Sheila Gwynne Classic, Miller believes it will be another nice mare, Generosity, who could spoil the party.

The Simon Miller-trained four-year-old is second-up after a fast-finishing second to Twain's Angel in the Marjorie Charleson Classic (1200m).

"She's a nice horse and I've got a lot of time for her," Miller said.

"She ran a nice race and went well the other day."

Miller's (Simon) horses have found the Sheila Gwynne Classic a lucrative race to claim in recent times with Amasenus and Stellar Vista going back-to-back in 2022 and 2023 respectively.

Miller has booked Lucy Fiore to ride Generosity, her first sit on the daughter of Divine Prophet, replacing Chris Parnham.

Generosity will jump from barrier two.