Taking to Instagram, the Vikings star shared a picture of herself mid high kick as she flung her foot up towards a man’s face.
However, despite looking pretty sharp – it turns out there’s a whole other story behind the snap.In the caption, the 41-year-old explained how the man had asked her in for the shoot, before wanting the actress to get her kit off.
He talked me into doing a martial arts photo shoot and then tried to convince me to do it topless.. No chance jerk!’
Warning her 3.2million followers, Katheryn said: ‘Ladies, watch out! #timesup #winkaiselfdefence.’
The star began training in Taekwondo at the age of 16, and not only has she gone on to achieve her black belt, but the director is now teaching her female Vikings co-stars self defense lessons on set.
When chatting to Entertainment Tonight, the Lagertha star spoke about her on behind the scenes classes and how she runs the WIN KAI Martial Arts Schools in Toronto with her brother Adam.
Katheryn had previously addressed the #MeToo movement, and how she hoped to inspire women through her character in the History Channel hit.
‘A lot of relationships of domestic abuse, especially now with the #MeToo movement, you see a lot of it coming forward. These women are strong,’ she said.