Donald famously took the field as a replacement in the 2011 Rugby World Cup, after the All Blacks lost Dan Carter and Colin Slade in matches before the final.
The All Blacks' fourth-choice first five ran onto the paddock just before half-time, after Aaron Cruden was injured, and kicked a crucial penalty late in the match that secured the World Cup win.
Donald famously got the call-up to join the squad while he was whitebaiting with a mate.
The whitebaiting season will have opened before the August 31 race meet in Hastings. Donald keeps his whitebaiting hand in, but wasn't sure if he'd have time to get a net wet in Hawke's Bay.
"I need to be getting organised,'' he said.
Hawke's Bay Racing CEO Andrew Castles said the club's partners Westbury Stud and the TAB had helped pull together fundraising initiatives for the Cancer Society.
"This is a great way to start the Bostock New Zealand Spring Carnival and a cause dear to our hearts."
Over the past five years Hawke's Bay Racing has raised more than $135,000 to provide care and support to local families affected by Cancer.
This year the TAB is doubling its donations, handing over $2,000 per winner in the Daffodil Raceday silks to the Cancer Society.
Donald will be the guest speaker at a High Tea for Hawke's Bay Cancer Society Volunteers.
Admission on the day is by $5 donation to the Hawke's Bay Cancer Society.