Turn a humble bathrobe or housecoat into a king's robe and you're ready for a fancy dress party. Royal robes were traditionally red, purple or black, and velvet has long been a favourite fabric for kings' robes, which were often decorated with ermine. There's no need to use such expensive fabrics for your costume, though: Velveteen and fake fur will still create a regal impression.
Measure along the hem of the robe, up each side of the front, around the collar and aound the sleeves. Cut fake fur into strips totalling that length. The width of the strip will depend on the size of the robe. Strips of approximately 4 inches wide are appropriate for a child's robe and 8 inches for an adult's, but vary the measurement according to the desired effect. The wider the strip, the more opulent the robe will appear.
Transfer black fabric paint into a dish or bowl, and use an artist's brush to dab paint in spots across the fake fur. The spots should be small and spaced well apart; you are aiming for an ermine effect, not Dalmatian. Allow the paint to dry.
Glue the fur strips along the borders of the robe, and allow them to dry.
Measure strips of gold ribbon the same lengths as the fur strips, and glue along the top of the "ermine" border.
Remove the belt of the robe and replace it with thick gold cord, knotted at each end. The cord should be long enough that will hang down from the waist to almost the bottom of the robe when it is tied.