Mary Kate and Ashley Olsen have dismissed rumours that a barista tried to sabotage them at their local coffee shop by replacing their usual skimmed milk for a full fat substitute.

The coffee maker in question, who works at the twin’s nearby Starbucks in New York, has reportedly confessed to committing the crime, claiming he was worried about their petite, skinny frames.

According to OK!, the girls regularly ordered fat-free beverages but, "the barista thought the Olsens were too thin, so whenever they ordered their usual drink, he would replace the skim milk with full-fat."

But a representative for the actresses has blasted the claims, insisting the story is "ridiculous".