People are convinced influencer's super fit mom is actually her sister

A Melbourne grandmother has taken Instagram by storm after her 20=year-old daughter shared a picture of the two of them together wearing similar swimsuits and flaunting their toned bodies.

When Sharon Orval's daughter posted the bikini snap on Instagram, she had no idea people would be so enamored by her youthful looks that they would actually confuse her for her daughter's sister.

Check out this video of the mom and daughter showcasing their in-sync dance moves:

Daughter Hannah - a lifestyle influencer with more than 227,000 followers on the social media platform - captioned the mother-daughter pic: "yeah this is my mum".

Now, the popular post has since received more than 28,000 likes and 120 comments - with many Instagram users in disbelief at Sharon's real age.

Many of the comments were incredibly complimentary of Sharon's youthful looks, but some of Hannah's followers were convinced the duo were actually sisters.

Instagram user laxwyzord commented with disbelief on the post, writing: "Mum? Are you sure? It looks like you spelt sister wrong". This was echoed by noelz001 who commented: "She could pass as your sister looking stunning girls".

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Another Instagram user with the handle danaschwass commented: "Sucks when your mums hotter than you hey", and a seemingly jealous whatsmineisyours_hire commented: "The genes in your family".

Speaking about the adoration, Sharon - who is actually 55 years old, if you can believe it - modestly told news.com.au: "I just think people are just kind […] clearly I don’t look like her sister but it’s nice of them to say something nice."

Sharon previously worked as a personal trainer before her online popularity skyrocketed. Now, she provides people with 'Shazzas Tips' through her social media accounts so they can hopefully look as good as her when they reach 55.

"I just sort of accidentally fell into giving people tips and then people would ask for more," she said.

"Before I knew it I was pretty much giving away the free tips which I had learned over the years that helped me and helped the other people that I was training as well."

And despite being retired, Sharon's passion for health and fitness is still going strong, hitting the gym five to six days a week (putting me to SHAME). She says:

"I go in there, I do as much as I can, I keep it moving. I try and get my cardio out of it as well. I like to train hard for at least an hour, and I like to train with weights, that’s something I’ve found that I enjoy."