The Harry Potter actress was photographed walking a brightly coloured pooch at the weekend, prompting concerns that the makeover could be causing distress to the animal.
In response to the story, Watson explained on Twitter that the dog - whose name is Darcy - belongs to her friend Sophie Sumner, an America's Next Top Model contestant who is attempting to raise money for breast cancer research.
She wrote: "I wish Darcy was my dog but she isn't : ( sorry daily mail! Was just walking her xx @sophiesumner @PinkDarcyDog.
"I don't have a dog. @PinkDarcyDog is pink because her owner is raising money for breast cancer...#factcheckingtakesfiveminutes."
Although "animal-friendly" vegetable dye is believed to have been used to colour Darcy, some critics have claimed that the procedure could still have a detrimental effect on the pet.
In a statement released following the Watson story, PETA said: "Dyeing a companion animal's fur causes the animal stress and can lead to complications or allergic reactions that endanger the animal's health.
"Our dogs and cats love us regardless of how we look; we should extend the same kindness to them."