Kathryn Mayorga, 34, claims the Portuguese football player raped her in a Las Vegas hotel room, according to German media outlet Der Spiegel. The magazine says Ronaldo paid her $375,000 for her silence.
The five-time World Player of the Year denies the allegations, insisting the sex was consensual. Mayorga's lawyer is now questioning the validity of an out-of-court settlement agreed in Nevada, in which Ronaldo reportedly paid $375,000 (€323,000) for her silence.
Der Spiegel claims the lawyer's case is based on a document containing Ronaldo's account of what happened on June 12, 2009. In it, the 33-year-old is quoted as saying "she said 'no' and 'stop' several times."
According to news agency Reuters, Ronaldo's lawyer Christian Schertz said in a statement the report was "an inadmissible reporting of suspicions in the area of privacy", and that he would seek legal redress for his client from the magazine.
Mayorga has now spoken publicly for the first time about her encounter with the Juventus forward, who was under contract at Real Madrid when the incident is supposed to have taken place, saying she was raped after spending an evening partying with Ronaldo while he was on holiday with his cousin and brother-in-law in Las Vegas.
Mayorga also described events following the incident, saying Ronaldo fell to his knees and told her he was "99 percent" a "good guy" let down by the "one percent."
Ronaldo is one of the most high-profile sports stars on the planet. The news is likely to attract global media attention, with the player and his legal team yet to respond publicly to the accusations.