Chocolate maker Mars has reduced the size of its Mars and Snickers bars, but kept the price the same.
The weight of a Mars bar has dropped from 58 grams to 51 and Snickers has gone from 58g to 48g.
Mars says it's to encourage people to eat more healthily and keep the number of calories (the energy contained) in a standard bar, to fewer than 250.
Last year, Cadbury's said rising cocoa prices forced them to shrink Dairy Milk bars and keep the price the same.
And it's not the first time Mars has reduced the size of a bar - in 2009, the size reduced from 62.5g to 58.
But it's not just chocolate makers - many other food items and other products sold in supermarkets are gradually becoming smaller, but costing the same.
A spokesperson for Mars said: "As part of our global commitment to promote responsible consumption, and as a signatory of the Responsibility Deal's calorie reduction pledge, we made a commitment to ensure that all of our single-serve chocolate products would contain no more than 250 calories per portion by the end of 2013.
"To meet our commitment, having taken product reformulation as far as we can for now without compromising the great taste, we have reduced the portion size of Mars and Snickers to bring down the calorie content."