The Moneyglass man will ride the race favourite Shutthefrontdoor in the showcase event at Aintree.
The 19-time champion, from Northern Ireland, will retire if he wins on a record 20th appearance in the race.
Punters are predicted to back his horse, trained by Jonjo O’Neill, so he becomes the shortest-priced National favourite since Red Rum 40 years ago.
One local bookmaker in Magherafelt told the Mail: “We have already had a huge number of bets on McCoy, and come race day, we expecting a lot more.
“There are people who bet on McCoy each year regardless of which horse he is racing, as he is a local lad, so we’re expecting a lot more bets on Saturday.”
According to the BBC, bookmakers are fearing a £50m loss if the legendary jockey wins the race.
Shutthefrontdoor is expected to start the race at a price of around 8-1.