He is only 14, but he will now have a big pair of shoes to fill, in fact, the biggest ever made by Under Armour.

Eric Kilburn Jr, who stands at 2.05m, will be receiving a pair of size 23 trainers from the US sportswear brand.

The Michigan high school freshman had been wearing size 22 shoes that were too small for him, leading to painful calluses, blisters and ingrown toenails, reported The Daily Mail. The average American man’s shoe size is 10½.

His mother, Mrs Rebecca Kilburn, issued a plea through a local newspaper to find shoes that fit her son, whom she said does not have a endocrine disorder that most other children this big and tall at this age have.

Under Armour responded to her appeal last Sunday and created a 3D render of Eric’s feet as well as a mould to make sure its designers created the perfect fit for him.

In a video on Michigan news site MLive, Under Armour’s senior director of footwear development Robb Cropp said: “This is my biggest foot ever... I’ve been doing this about 30 years and I’ve never had anyone this size.”

A grateful Eric, who will also be receiving a pair of custom-made cleats in time for the upcoming football season, said: “Just having shoes that don’t cause blisters or pain on my feet would mean the world.

“It felt great just knowing that this is the first step in the line of getting new shoes.”

Other brands such as Puma and Mauri have also came forward to offer similar help to the teen.

Mrs Kilburn told USA Today that the companies’ gestures restored her faith in humanity.

“I hit so many dead ends with people laughing when I called to ask about shoes. It was a very lonely feeling. And now we’re overflowing with support, generosity and kindness,” she said.

“It’s been overwhelming. I have been this puddle of emotions, all of them good… It’s the coolest thing to be able to say we did it!”

The mother-of-two had previously spoken about the family’s struggle to make sure Eric was properly clothed.

She shared that at one stage, Eric was forced to wear Crocs for two years, even during the middle of winter because there were no other options available to him apart from the pricey $1,500 (S$1,994) custom orthotics that he would quickly outgrow.

A GoFundMe has so far raised almost $23,000 (S$30,600) for the family to buy Eric shoes that fit, and Mrs Kilburn also started a Facebook group called “Big Shoe Network” to help people find large shoes for them to buy.