Nestlé is replacing its Kit Kat Chunky with a two-piece bar called Chunky Duo. At the same time a new Chunky peanut Duo is being added to the range. Recommended retail price for both products is 58p.
The company says the launches are in response to consumer demand for portion control packs.
Meanwhile the Kit Kat Senses brand will be backed by a Girls Aloud promotion throughout September. One hundred and sixty five t-shirts in five different designs will be given away every day of September to highlight the 165 calories in each bar. The activity supports the Make-A-Wish Foundation, the charity that grants wishes for terminally ill children.
Senses was launched in March and so far more than 23 million bars have been sold, achieving more than £9m-worth of sales.
The promotion will be backed by press advertising and pos featuring Girls Aloud.