Threepipe won the six-figure account following a six-way pitch.
The chilled baby food range aims to capatalise on a market worth £458m a year. It will launch later this month, initially via Waitrose and online supermarket Ocado.
The PR programme will target parental bloggers, food journalists and key opinion formers in the baby and food sectors.
Highgrove's communications strategy will focus on highlighting the benefits of chilled baby food.
Other Highgrove brands include Gold Top milk and Goose Fat, as well as its dairy licensed brand Noddy yoghurts.
