In September, Mr Smith's popular children's book Wonky Donkey made global headlines after a Youtube clip of Scottish grandmother Janice Clark, unable to contain her laughter while reading the book to her grandson Archer, went viral.
Since that time, US publisher Scholastic had informed Mr Smith it planned to print an additional 500,000 copies to meet renewed demand.
Although the clamour for his book had been matched by an increased demand for public performances, Mr Smith said he was looking forward to honouring his long-standing appointment at tomorrow's South Otago show.
"I won't see royalties from the global sales for six months so nothing has changed for me right now. However, Janice the Scottish Granny was recently flown business class to the flagship Barnes and Noble store in New York to do a reading of Wonky Donkey. But the joke is on her, really, because I get to travel to Balclutha in my Hiace van."
Teacher and donkey breeder Judy Weild, of Lovells Flat, near Milton, said she had met Mr Smith and enjoyed his book.
"My pupils and I all love the book. It certainly brings a lot of happy attention to these lovely animals."
Mrs Weild was pleased to see the A&P show's donkey section return for a second year.
"We've got seven donkeys and an ass here, but I'll probably only take two with me on Saturday."
• South Otago A&P Show, Balclutha Recreation Centre, Glasgow St, Saturday 9am-4pm.