Ruby Rose eviscerates celebrity dietitian for making "reckless" comments about her weight.

As any woman in the public eye knows all too well – when it comes to magazine coverage of your body, you can’t win. You’re either deemed too fat or too skinny and it is always, always something to be ashamed of.

Ruby Rose is one star who has – according to the tabloids – been “too thin” for years, and the Aussie actress has had enough of it.

The 31-year-old responded to dietitian Lisa DeFazio’s opinion of her weight printed in Star magazine, where she estimated Rose weighed 44kg and said her “family and management team need to encourage her to gain some weight before it’s too late”.

Rose hit back on Twitter, telling DeFazio she was "reckless", "maddening, and irresponsible" for speculating on people's weight without any knowledge of them.

"Do you actually have any ‘celebrity clients’ or just gossip magazines? You comment on people who you deem are too big or too small and even go so far as to guess why.

"You are reckless and no Hollywood expert would behave the way you do."

The model added she'd probably be in hospital if she weighed so little.

"I have the best team, family, friends, partner and medical professionals (not the ones who want to be TV hosts but actual credible Eastern and Western doctors) and I'm running at an optimum level. I am deficient in nothing and have endless energy."

Rose also threatened to knock the woman "off your pedestal of self-serving bullshit".

"I’d out train you, out box you, and sleep better at night.. Leave people alone."

DeFazio defended herself on Twitter, saying her comments are "never meant to be judgemental or body shame".

"Based on images they send me, they want me to explain health risks associated with various nutrition issues including being overweight or underweight- BASED ON MY EXPERIENCE in the MEDICAL field. It is all in the spirit of education and awareness," she wrote.

This isn't the first time Rose has addressed an outsider's concerns over her health and weight on social media.

In her Instagram Stories last month, she posted a message aimed at body-shamers.