Ms Grant who reported the image to her Instagram page today wrote alongside it how the past week has been so amazing, thanking Benefit UK.
Her proud mum Deirdre Grant said she has a great drive to be a supermodel, Metro UK reported.
"I love her optimism and as her mum I would always be there to support her in that optimism," her mother said.
"'When you are young you think the sky is the limit and with Kate she does not have the understanding that we have that there are obstacles in the way.
"She does not allow obstacles to be in the way or her disability to stand in the way.
"She would say Down syndrome does not define me — I am Kate."
Since the image was posted to Benefit UK's Instagram page last week, it has gone on to receive nearly 5000 likes.
"Kate is aware of that and wants to spread awareness about inclusion for people with disabilities and that is what she has done from the very start."
"She is aware that she is able to do that in a way some of her friends cannot. She is using her voice for them."
Many social media users have commended Benefit for using the aspiring model to represent their brand.
"What an inspirational young lady, thank you Benefit for the heartwarming equal chances with your models. And for the amazing makeup obviously," one user wrote underneath the image.
A recent post from the cosmetics company reads: "WING WOMAN WEDNESDAY. Introducing our first #wingwomanwednesday the gorgeous @kategrantmodel.
"We're so pleased to have her as one of our Wing Women."
Instagram users were also quick to praise the model.
One wrote: "What an inspirational young lady, thank you @benefitcosmeticsuk for the heartwarming equal chances with your models! And for the amazing make up obviously."
Another wrote: "She is the prettiest and you are the coolest."
Down syndrome is caused by an extra chromosome in the cell and entails learning disability and potentially a range of other health problems.
