The appointment comes as the firm prepares to launch its Reese brand in major supermarket chains across the country.
The brief includes three products in the Hershey portfolio: Reese's Peanut Butter Cups, Reese Sticks and Reese's Nutrageous.
Fuel PR managing director Gillian Waddell said the account comprises trade and consumer PR work, seeking to raise awareness of the brand among 'trendsetters'.
She said Fuel would target 'a cult, niche, consumer audience' of 'trendsetters' in addition to work targeting mainstream consumers.
In the past the Reese range has only been available in the UK through a limited number of independent stores, but major chains are to begin to stock the products from later this month, according to Waddell.
On the trade PR side, Waddell said Fuel's role would be 'to ensure Hershey and Reese have a strong profile with grocers, firms with mulitple outlets and independents in the UK.
Account manager Gemma Parkhouse leads a three-strong Fuel team, reporting to the Hershey International division in the US.
Hershey Foods is a market leader in the US but sales in countries outside North America account for less than five per cent of the company's revenue.
Late last summer it was reported that Swiss-based food giant Nestle had offered around £7.5bn for Hershey, although this bid came to nothing.
Hershey's future has been subject to speculation after the Hershey Trust, which controls 77 per cent of voting shares in the firm, revealed efforts to sell its stake.
- Fuel was last month appointed as the PR agency for California Lines, a Wella Group-owned business. Fuel is to promote the Sebastian Hair and the Sebastian Trucco make-up ranges.