Personal coach Lesley Maxwell says "age is just a number" as she trains people to get into shape.

The Australian grandmother is not shy about showing off her hard work; on her Instagram, she flaunts her bikini body and skimpy gym wear.

In a snap with her granddaughter, Lesley captioned the snap: "My granddaughter @tiachristofi and I share a love for health, fitness and apparel?"

In amazement, fans of the fitness fanatic jumped to the comments section to share their thoughts.

Djwilliams1119 said in disbelief: "That’s your granddaughter?!" Lopsabrina_ joked: "Who is one and who is the other?"

Juliesudlow echoed what other people were thinking by adding: "Omg, looks like your sister???"

Elena.chatfield said: "Gorgeous! Very inspiring to your beautiful granddaughter."

Lesley is "passionate about helping people to be healthier, happier and feel young and sexy at any age".

For her, Lesley's body transformation began after she separated from her then husband in her late 40s.

Ever since the relationship breakdown, Lesley has gone on to take part in more than 30 figure competitions and has been titled World Champion.

In her lastest Instagram video, posted only five hours ago, Lesley revealed her workout routine.

"My workouts consist of staying in that eight to 10 rep range so I really focus on pushing myself with perfect form," she said.

In her set for the upper body workout, Lesley includes a machine chest press, dumbbell bench press, cable fly, and barbell incline chest press.

All of these moves are showcased on the video so that people can see what they need to be doing at the gym.

Yaxcharlie said: "Wow! You are a very, very beautiful and gorgeous lady! Keep up the Great Work! Wow!"

Feeling empowered, Lesley even posted a picture of herself in her lacy bra, proving older women can still be desirable.

Lct196 said: "Thank you for sharing, you look incredible." Mikephotog said: "Perfection."