As Australian racing loses Black Caviar and All Too Hard, their half sister Belle Couture is ready to begin her career in earnest.

After pre-training out of town, the two-year-old will arrive at Danny O'Brien's Flemington stable on Tuesday in preparation for her racecourse debut late in the season.

Speaking on behalf of her owners BC3 Thoroughbreds, Simon Marshall said connections had been patient with the filly and were thrilled with her progress.

"Slowly but surely she has told us she wasn't in any rush to be pushed and we've just followed her lead," Marshall told racingvictoria.net.au.

"She can get in there and have a full experience in the stable and can get to know she is a racehorse.

"She's grown out to be a lovely, big girl and a very good size like her mother."

Marshall said Belle Couture, by Redoute's choice out of Helsinge and a $2.6 million yearling at the 2012 Inglis Sydney Easter Sale, was likely to make her racetrack debut in June or July with a number of feature races during the Melbourne spring under consideration.

"There are a number races that we'll put on the table but at this stage she's just got to have a good experience and get a full preparation under her belt and we'll go from there," Marshall said.

"The beginning starts now and she's ready to go."

At this year's Easter sale, BC3 paid an Australasian record for a yearling, securing Black Caviar's half by Redoute's Choice for $5 million.

The colt will be trained by the Hawkes family partnership which also has All Too Hard in its care.

All Too Hard threw down the challenge to Black Caviar for Horse of the Year honours when he claimed his third weight-for-age Group One win in Saturday's All Aged Stakes and his fourth for the season.

He is scheduled to go to England for the Queen Anne Stakes at Royal Ascot in June before joining Vinery Stud's stallion roster in the spring.

Black Caviar's swan song came two weeks earlier when she won the TJ Smith Stakes after which she was retired with an unblemished record of 25 wins from 25 starts.

The decision on which stallion she will visit has not yet been announced.