Kim Kardashian reveals secret of her enviable fitness

American star Kim Kardashian put her toned body on display as she took fans through the steps of her morning weight workout in new stunning video.

The mother-of-four, 42, appears to be a fitness diva in new video which she shared on her Instagram Story Sunday.

Kim looked stunning as she showcased her fit figure in a black top and leggings during a grueling workout session. She wore a little makeup and styled her hair in a loose updo with tendrils in front.

The Kardashians star updated her millions of followers writing, 'It's been three months now working out with @senada.greca.'

She described her activities in a lengthy note: "We lift weights for two hours daily and do 5 or 6 days a week,' she explained as she place a bar loaded with 40 pounds of weight on her shoulders and began to squat with one heel lifted off the floor in what she and her trainer call a 'split stance good morning."

She also explained her goal: "My goal was to gain muscle and be strong and I see such a difference already. I'm proud of our commitment together. It always starts with small goals."

Kim appeared to be a professional athlete as she placed a red exercise band around one leg to provide added resistance as she placed her feet together and then squatted with her legs hip width apart.