The agency is understood to be working on a TV-heavy campaign to relaunch the brand later this year, although it is unclear whether this will focus purely on above-the-line activity or if it will include an integrated and below-the-line element.
Coke's media agency, BBJ, will handle the buying and planning for the account, which has been dormant for three years.
It is thought any activity will hinge on Coke reasserting the brand's values to its core audience of families and mothers. The drink is traditionally a staple of children's school lunch boxes.
It is thought that Soul won the task without a pitch on the back of its work for Coke's Fanta brand. The animated TV ad features a cartoon boy who seeks out the orange taste of Fanta on everyday orange objects.
The last above-the-line ads for the Five Alive brand were created by the then-roster agency Leo Burnett in 1998. The £1.5m television campaign featured a fantasy fruit, called orangraptang-lilem, which was flavoured with the fruits in Five Alive and had been discovered growing undisturbed on a tropical island.
The ads ran alongside PR and promotional offers, and came as Coke relaunched the brand with new products, formats and packaging. Since then, the brand's marketing has focused purely on on-pack promotions, with the last one, linking the product with Legoland in Windsor, running last summer.
No one at Coca-Cola, Soul, or BBJ would comment as Campaign went to press.
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