The former England international footballer has a share in the five-year-old mare as part of the celebrity-laced Masters Syndicate which also includes Lee Westwood and Ant and Dec.
Augusta Kate has looked the real deal in two starts in Ireland and is towards the head of the market for one of the fiercest betting heats of the week.
Shearer said: “We will have a great day whatever happens.
“Her trainer Willie Mullins believes if she produces what she has done in her previous racecourse runs so far, she will have a chance as nothing as stood out from the pack in the race.
“She’s a horse which does not show too much at home but we are just keeping our fingers crossed for a big run.
“Graham Wylie put the syndicate together for days like this but we never expected to have one of the fancied runners in a race at the Cheltenham Festival.
“She’s produced more than we would have hoped. If the best happens, I might not come home Wednesday night. She’s running in the last race on the card so I should not feel any pain at that point,” he told Coral.
Mullins added: “Augusta Kate is impossible to rate. You have seen what we’ve seen because she shows nothing at home.
“I don’t know if it’s our gallop or the way we train, but she doesn’t show us any ability.
“Indeed, when I went down to Listowel with her, Graham asked if she was any good because he wanted to put some friends into a syndicate. I said we would win something, as in a summer bumper somewhere, but she won by 18 lengths and then won a really good mares’ bumper by 12 lengths.”
Mullins has won the Champion Bumper a record eight times and also saddles Avenir D’Une Vie, Bacardys, Battleford, Castello Sforza, Turcagua and Very Much So.
Dermot Weld’s First Figaro and Winsome Bucks, an easy winner at Leopardstown over Christmas, add to the Irish hand