The "touch of luxury" rainbow candle uses a heat-sensitive light sensor that creates a "kaleidoscope" of pastel colours when the candle is lit.
The candle is available in "seasonal fragrances", including mulled wine and cinnamon apple, rich vanilla and caramel swirl, and cocoa truffle and cream.
The new product is being supported by TV, in-store, print and digital activity launches 10 October and runs until the end of the year.
Last week, Marketing revealed that RB will be launching a £10m marketing push for three of its over-the-counter brands in October.
It marks the first time that the Lemsip, Strepsils and Meltus brands have been pulled together under the same brand message.
