The agency beat at least one other undisclosed shop to take the business.
A TV, press, ambient media and promotional campaign is expected to be unveiled in the summer.
Capri-Sun competes in the children's drinks market against the likes of Ribena and Sunny Delight. Its above-the-line advertising has been dormant in recent months. Magnetic North, the digital agency formed by a breakaway from J. Walter Thompson in 2000, was appointed to work on promotional and interactive projects for the brand in 2001.
It was also responsible for creating the brand's most recent TV campaign, which introduced a character called Frooster, who was developed as the latest member of Capri-Sun's brand gang called the Juiclings.
The ads ran on children's channels including Nickelodeon and citv.co.uk.
VCCP already handles the global creative account for Appletise, which is marketed and distributed by Coca-Cola Enterprises in the UK.