The offer is likely to be worth around £120m (€177m), though the company emphasised that the talks are still in an early stage and the proposal remains subject to a number of pre-conditions.
The news comes just 18 months after previous talks of a potential buyout were aborted, leaving the company with a £626,000 (€922,000) bill.
orporate finance company Seymour Pierce believes that Thorntons is indirectly opening its doors to further takeover bids.
"We believe that they included the potential buyout price in the statement as a representation of the base level from which they would be willing to receive offers from other companies," analyst Rhys Williams told ConfectioneryNews.com.
Thorntons was unable to comment on the speculation.
In a trading update ahead of its annual results, the Derbyshire-based company recently announced a 5 per cent increase in sales for the 2005 financial year, up to £188m (€278) compared to last year's £179m (€264m).
For the last two years, Thorntons has been gradually stepping up sales of its boxed chocolates and other confectionery products through the mainstream food retail sector, resulting in a significant sales boost in the past year.
The company's own-shop sales fell one per cent, though the decline was offset by a more than doubling of sales through other retailers, such as supermarkets Tesco and Sainsbury's, to £22m (€32m).
Burnett said the company's performance was "encouraging in a difficult trading environment."
In February the company had said it planned to improve its own network of stores and range of products in order to secure its future.
"We have some major improvements still to make in our manufacturing business," chief executive Peter Burdon had said. "Areas such as planning and production efficiency need to be improved, and we also have to look at slimming down the range of products we make. Above all, though, we must improve our packaging, which I feel has not moved with the times and looks somewhat outdated. The increased profits from efficiency gains will of necessity be ploughed back into these other areas."