Lexus Stakes winner Signoff has been joined by Unchain My Heart in claiming the last two places in the Melbourne Cup.

Signoff earned his berth with an automatic entry after a clinical victory over Big Memory in the Lexus at Flemington on Saturday.

Unchain My Heart, certain to run the rank outsider on Tuesday, made her way into the race when the 2012 Cup winner Green Moon was withdrawn before acceptance time.

The David Hayes-trained mare was due to run in the Lexus but stewards allowed Hayes to withdraw the eight-year-old from the race after a Cup berth was all but confirmed.

She could have been left on the outer if Lloyd Williams' Amralah had figured in the Mackinnon Stakes placings but the import disappointed at his first Australian start.

Twenty-four runners will line up in the $6 million Cup with Admire Rakti and Signoff emerging as the top two favourites before the barrier draw.