In a champagne flute, combine the grape juice and bitters. Top the flute with the Champagne.
Express an orange twist by removing the orange zest from the pith. Using a sharp knife, cut along the outside of the orange removing as much of the skin as possible and taking as little of the white. Squeeze the orange peel on top of the drink to express the citrus oil. Discard the peel.
We find that any relatively dry sparkling wine works for a bubbly champagne cocktail.