The public were encouraged to tuck into the advert, located outside Westfield London in Shepherds Bush, from midday until 8pm.
There were 13,360 cakes used to create the piece, which formed part of Mr Kipling’s ‘Life is better with cake’ campaign.
JWT London worked with digital agency Outside Line, media agency Carat and PR agency Cirkle to launch the activation.
Lisa-Jo Harvey, senior brand manager at Premier Foods, which owns Mr Kipling, said: "We can’t think of a better way to show people that life is better with cake than to create an edible poster made out of thousands of our exceedingly good cakes."
David Masterman, creative director at JWT London, added: "If Mr Kipling himself was doing a poster, he'd make it out of cake."
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