Promising two-year-old filly Katy's Daughter is out of the Magic Millions Classic after suffering a knee injury.

Katy's Daughter had been safely in the Classic field for January 13 at the Gold Coast with $60,200 prize money from a win and second..

She gave Group One winner Epaulette his first winner at the Gold Coast two weeks ago and had been at $26 in Millions Classic markets.

Trainer Steve O'Dea said she had been found to have a chip in the nearside knee and would have surgery.

"She is expected to have an operation next week. It is bad luck but I suppose that is two-year-old racing," O'Dea said

"The tracks have been very hard. I expect she will come back a good horse again."

It is double blow for O'Dea as the filly is a daughter of his favourite broodmare Kiss Me Katy and he would have loved her to go down as the dam of a Magic Millions winner.

O'Dea has also qualified Singular Sensation for the Millions Classic and the unbeaten filly is expected to go straight into the race without another run.

His best effort in the Millions was with Candika who ran third in 2016.

First season sire Epaulette will be represented by the Lee Curtis-trained Meryl in the Classic after her win in Saturday's B J McLachlan at Doomben.