The event will raise funds for the charity, set up by the late Connie Johnson (sister of gold Logie winner Samuel Johnson), which will in turn donate it to the Garvan Institute of Medical Research.
The local event will see people donate $50 to take part in a huge art project featuring small tiles with heart imprints.
Each donor will imprint the heart shape with their thumbs and have their tile included on the final project, to be hung at the Garvan Institute.
The heart tile campaign has been so successful that there are just 38 tiles remaining.
Anyone wishing to donate and create their own tile must register online at eventbrite.com.au.
The event will see the castle decorated in pink for the occasion, with face-painting and treats also available.