Actresses Mary-Kate Olsen and Ashley Olsen have laughed off rumours a barista at their local coffee shop has been secretly trying to fatten up the stars — by substituting their usual skimmed milk with a full-fat version, reports.

A worker at the twins’ local Starbucks outlet in New York has reportedly confessed to altering the sisters’ morning drinks because he was concerned about their skinny frames.

According to OK! magazine, 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 Olsens has blasted the claims, insisting the story is “ridiculous.”