The 64-year-old woman who swam from Cuba to Florida without the aid of a shark cage is set to answer her critics over whether she cheated.
Diana Nyad has been hailed by many across the United States, with President Barack Obama saying her achievement showed people they should "never give up on your dreams".
ITV News' Lucrezia Millarini reports:
However, there have been questions over her rapid speed with some claiming that Nyad could not have swam as fast as she did without help.
Nyad, who will meet her critics and answer questions on the swim today, said her speed was down to the fast-moving Gulf Stream current.
The 64-year-old finished the swim on September 2 after around 53 hours.
Her progress was tracked by a satellite and questions over her feat were raised after it emerged that for one seven-hour period, Nyad apparently did not stop to drink or eat.