MATT and Melanie Cullen hope every step they take on the five-kilometre Walk to Cure Diabetes this Sunday will be a step closer to finding a cure for the chronic disease that affects their little boy.

Already the Harrington Park couple have raised $9100 for the Juvenile Diabetes Research Foundation whose mission it is to find a cure for type 1 diabetes.

Their three-year-old son, Will ``Superman'' Cullen, was diagnosed with type 1 diabetes in May 2007.

``He got very sick all of a sudden,'' Mrs Cullen said. ``He'd been vomiting and we thought it was just a gastric bug.

``By that night we were in hospital and then Will was being transferred to Randwick.''

That was the start of Will's daily regime of needle pricks and multiple insulin injections to stabilise his often unsteady blood sugar levels that have at times fluctuated from 2 to 27.

Nine months later he received an insulin pump he has nicknamed ``Percy''.

The pump, attached to Will's body by a long piece of tubing inserted under the skin, delivers insulin around the clock and means he no longer needs injections.

The only time you'll catch a frown on Will's face is on ``set day'', when the Cullens have to replace the disposable infusion set where three days' worth of insulin is stored.

In a bid to raise money to find a cure for juvenile diabetes, the Cullens posted a four-minute video on YouTube called ``A brave little boy's story''.

The ``tear jerker'' movie gives an insight into Will's life and what his parents call the ``unrelenting demands of diabetes.''

The video tracks Will's life so far as a happy baby to the now boisterous toddler showing off ``Percy the pump'' which he has ``because I'm diabetes''.

Sixty of the Cullens' family and friends will join them on their Walk for Diabetes at Olympic Park. They'll don Superman style T-shirts bearing a W - for Will and for the team's name, Will's Warriors.