Air is a good feature for a cat carrier to have but her hiking habit has come under fire from various pro-cat organisations.
"We don't advise people taking their cats out unless absolutely necessary as they are very territorial and crave freedom of movement," said Daniel Cummings, behaviour manager at Cats Protection. "Placing them in small and confined spaces and taking them to unfamiliar environments will cause a lot of cats stress."
People for the Ethical Treatment of Animals (PETA) also weren't down with the cat backpack that Kidman was picking up.
"Most cats would prefer to lounge indoors than to go hiking," PETA UK's director Elisa Allen said, before conceding that, "all cats are different, and it's possible some may enjoy the outdoor experience."
While hiking has many health benefits for humans, including fitness and state of mind, Cummings says carrying a cat in this fashion is not likely to lead to improvements in their health or wellbeing.
"It's unlikely that an experience like this will be beneficial for most cats," he told the Guardian.