Ryan Reynolds designed the shirt for this year's Terry Fox Run and the response has been 'overwhelming'

The Terry Fox Foundation has announced that this year's shirt honouring one of Canada's most inspirational figures was designed by Ryan Reynolds – and the response has been "overwhelming."

The Terry Fox Foundation has announced that this year's shirt honouring one of Canada's most inspirational figures was designed by Ryan Reynolds – and the response has been "overwhelming."

Reynolds posted a photo of himself Saturday, wearing the shirt and alluding to his involvement with this year's fundraiser for cancer research.

"I’ve been taking part in the Terry Fox Run since second grade and can’t think of a more enduring and lovely legacy for one person. Terry Fox inspired millions in life and death," he wrote.

After a flood of people asked how they could get the shirt themselves, the charity posted online saying "Secret's out" and announcing that it had been designed by Reynolds and would be available to registrants for the annual run on April 12 – the 43rd anniversary of the start of the Marathon of Hope.

But that didn’t seem to satisfy people who wanted to get their hands on Reynolds' design while contributing to a good cause.

On Sunday morning, the Terry Fox Foundation announced that it would be launching a pre-sale of the shirts due to the demand. According to the organization's social media posts, the move is unprecedented as is the demand.

The shirt itself shows Fox set against a background of the phrases "Dear Terry" and "Cher Terry." The text looks handwritten and the design was inspired by "the countless messages Terry received from the millions of people he continues to inspire," according to the foundation's website. The back of the shirt shows actual letters received by Fox. One reads simply: "Run, Terry, run." Another says, "You are my greatest hero ever."