US chocolate giant Hershey has extended its Bliss Chocolate range with the addition of a white chocolate line.

Hershey's Bliss White Chocolate with a Meltaway Center is available in 8.6oz lay-down bags at mass, grocery and drug stores across the US from this month, the company said today (1 December).

"Hershey's Bliss White Chocolate joins the celebrated Hershey's Bliss Chocolate portfolio adding to the delicious variety of the award-winning chocolate collection," said Hershey spokesperson Jody Cook.

As part of the launch, Hershey is offering women an opportunity to win a competition to share a 16.5 carat diamond necklace for two weeks, along with a variety of Hershey's Bliss chocolates, a bag of the new Bliss White Chocolate and a signed copy of "The Necklace."

The winners of the Hershey's Bliss Chocolate necklace will be invited to meet in New York at the Young Survival Coalition's spring 2010 charity benefit. During the event, the necklace will be auctioned to benefit the YSC, an international organisation for young women and breast cancer.