Starting Tuesday morning, Nyad will swim continuously in a pool that will be erected in New York City's Herald Square, CBS News reported.
"I'm from New York City and last year I was in town right after Sandy hit ... . You feel such tremendous compassion for people," Nyad told CBS News. "You might sit down and write a little check for disaster relief -- whatever you can afford ... And then its' not front page news and you forget about it .... Well thousands of people haven't forgotten about it -- Jersey Shore, Staten Island, Far Rockaway -- all over New York and New Jersey."
So far, the event, called "Swim for Relief," has raised $29,704.
"It's going to be a spectacular, fun event. For me, not so fun -- 48 hours I take seriously," Nyad said. "When it's over we're going to give a big fat check to AmeriCares and all that money goes will go right to Sandy relief."
Celebrities slated to appear at the event include Olympic gold medalist Ryan Lochte, "True Blood" actor Joe Manganiello, actress Nikki Reed of "Twilight," New York Giants player Justin Tuck and comedian Michael Ian Black.
Nyad completed a record-breaking swim from Cuba to Florida in September.
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