This costume is two halves forming a total; one side showing a man in suit and top hat, and the other side showing a woman in flouced skirt and a veiled face. The bodice consists of a bright waistcoat combined with a red/golden boned bodice with frills. They're both pointed in front. The female part has pagoda sleeves, while the male part has a stripy jacket reminding of a tailcoat. The skirt is made up of layers and layers of different fabrics, while the pants are made of a thick black satin. Half of the headgear is a top hat, while the other side has netting and flowers arranged over feminine ringlets. The costume also includes a halfmask and half a moustache, and a black cloak lined with red and yellow satin.

The original West End version of this costume was made of approximately 15 metres of fabric and 60 metres of braid (including the cloak). It was made by a husband and wife team, where he made the male part and she made the female part. This according to "The Complete Phantom of the Opera" by George Perry.

The costume is usually worn by one of the male dancers, and with the cloak he is echoing the threat of the Phantom - something that keeps frightening Christine.

Similar ideas can be seen in historical sources, for example an etching from the early 18th century. It shows quite precicely the idea of Maria Bjørnson, with half the outfit being male, and the other one female, with each side mirroring the shapes on the other side. The drawing look quite allegorical to me, maybe something about fashion and gender - certainly not how a person would dress in the 18th century. This was also a popular fancy dress idea in the late 19th and early 20th century.