Cut the watermelon in half and cut a 2cm/¾in slice off one of the halves. Stamp out 3 stars or flowers out of the slice. Scoop out balls of watermelon from the other half using a small melon baller.
Remove the skin and core of the pineapple and cut two 2cm/¾in slices off the pineapple. Stamp out 3 stars or flowers using the cutters. Slice the remaining pineapple into cubes.