Arnold Schwarzenegger used to throw daughter Katherine’s shoes into the fire to teach her a lesson

Arnold Schwarzenegger has revealed he used to throw daughter Katherine’s shoes into the fire in a bid to teach her a lesson, having opened up about his unorthodox parenting techniques in his new book.

Schwarzenegger, 76, is dad to Christopher, 26, Patrick, 30, Christina, 31, and Katherine, 33, all of whom he shares with ex Maria Shriver.

He also has an illegitimate son, Joseph Baena, who is the son of his former housekeeper – the child born just days after Shriver gave birth to Christopher.

Schwarzenegger is now speaking about the lessons he’s learnt in life as a dad, actor, bodybuilder and governor in a new motivational book, Be Useful: Seven Tools for Life, which is out next month.

“Written with his uniquely earnest, blunt, powerful voice, Be Useful takes readers on an inspirational tour through Arnold's toolkit for a meaningful life,” the book’s website says.

“Arnold shows us how to put those tools to work, in service of whatever fulfilling future we can dream up for ourselves. He brings his insights to vivid life with compelling personal stories, life-changing successes and life-threatening failures alike - some of them famous, some told here for the first time ever.”

It adds: “Too many of us struggle to disconnect from our self-pity and connect to our purpose. At an early age, Arnold forged the mental tools to build the ladder out of the poverty and narrow-mindedness of his rural Austrian hometown, tools he used to add rung after rung from there.

Penguin Random House

“Now he has shared that wisdom with all of us. As he puts it, no one is going to come rescue you - you only have yourself. The good news, it turns out, is that you are all you need.”

Speaking to PEOPLE about the new book, Schwarzenegger opened up about the unique approach he had to imparting his own wisdom when parenting his kids.

He admitted he used to throw his daughter’s shoes into the fire as a lesson about tidiness, saying: "You could talk to them about what they liked about their upbringing because they have very humorous stories.

"The first one is Katherine ... As a matter of fact, Katherine comes over with [her 3-year-old daughter] Lyla and she says, 'Lyla, I told you already not to put the shoes there. Keep your shoes on or you put them away, but you don't leave them there by the stand in front of the fireplace because you know what Daddy did? When I left my shoes there twice? The third time, he burned them in front of me and I cried.'"

Ouch.

Instagram/@katherineschwarzenegger

Schwarzenegger also recalled a time when Patrick was nine, and he’d thrown his mattress out of the window after his eldest son failed to make the bed.

He continued: "I opened up the door to the balcony, picked up the mattress and threw it down with the bedsheets, the pillows, everything. I said, don't ever make someone come in and clean your room, clean your shower or make your bed.

"I said, 'Because I taught you how to make the bed.'”

He would also tell his children off if they had long, hot showers.

Schwarzenegger told Patrick: "It's over, no more showers. Five minutes, one shower, and then that's it and we're turning it off."

Be Useful: Seven Tools for Life is out on 10 October.