The rugby star, who's also illustrated seven children's books, said painting an egg was different to working on paper. The egg is named Gilbert, after the ball brand, and it gives a nod to the Blues and Auckland rugby teams.
"I have a few things on that egg that I love, plus a big ear and a crooked nose."
The 35-year-old test-match veteran is a little nervous about having his work on display. "Playing in a packed stadium, that's my zone - that's what I feel comfortable doing, so [painting the egg] was a really enjoyable challenge."
Other artists who have created eggs include Herald cartoonist Rod Emmerson, Reuben Paterson, Dick Frizzell, Erika Pearce and Flox.
For those keen to get in on the hunt, there are prizes for those who find the eggs, on display until April 7.
The eggs will also be auctioned - 80 on Trade Me and 20 at a gala cocktail evening on March 31.