The dress was created by a team of three chocolatiers to celebrate Magnum’s 25th anniversary and took about 100 hours to make.
It used enough chocolate to create 833 Magnum Classics ice creams.
In total, 25 of the dresses have been made and will all be given away to people who enter a competition on its social media accounts.
To be in with a chance of winning, entrants must find three codes on Magnum’s Facebook, Instagram, Pinterest and Twitter accounts and tweet using the hashtag #MagnumDressCode.
Designer Holland said: “The starting point for the dress was obviously the Magnum itself and so we worked on the idea of cracked chocolate.
“Another first for me was having something I’ve designed made in chocolate and I’m so excited to see how they interpret the dresses, because it’s probably one of the most detailed pieces I’ve created.”
Earlier this year, drinks firm Drink Me unveiled a dress made entirely of tea packaging at London Fashion Week.