Four-time Olympic champion Simone Biles says she was sexually abused by former Team USA gymnastics sports doctor Larry Nassar.
In an emotional statement, Biles, a star of the Rio Games, said she would not let Nassar “steal my love and joy”.
Nassar was jailed for 60 years for possessing child sex abuse images and has also admitted assaulting gymnasts.
“I know this horrific experience does not define me, I am much more than this,” said Biles, 20.
Three former US Olympians have accused Nassar of sexual abuse under the guise of medical treatment, including Gabby Douglas, who won gold with Biles in the team event at the 2016 Rio Olympics.
Nassar faces two criminal cases where he admits assaulting female gymnasts, and will be sentenced this month.
The 54-year-old was jailed in December for three counts relating to child sex abuse images on his computer.
“I too am one of the many survivors that were sexually abused by Larry Nassar,” Biles wrote in a statement on Twitter.
“Most of you know me as a happy, giggly and energetic girl. But lately, I’ve felt broken and the more I try to shut off the voice in my head the louder it screams. I am not afraid to tell my story anymore.”
She added: “It is impossibly difficult to relive these experiences and it breaks my heart even more to think that as I work towards my dream of competing in Tokyo 2020, I will have to continually return to the same training facility where I was abused.”