In an exclusive interview with Robin Roberts on Good Morning America Friday, Upton said she felt a sense of relief after telling Time Magazine that Marciano verbally harassed and grabbed her breasts when she was starting out as an 18-year-old model.
"It had a huge emotional impact after, because it made me question what I was doing, how I put myself out there to be treated in this way," Upton said.
She also claims she was fired from a job for refusing to go to his hotel room.
Marciano has denied the allegations calling them "false and preposterous."
He also said in a statement to Time: "I have never been alone with Kate Upton. I have never touched her inappropriately, nor would I ever refer to a Guess model in such a derogatory manner."
Upton responded to his denial on GMA, saying, "I don't really need his validation for what happened, so I'm not looking for him to come out forward and tell the truth."
Her husband, Astros star Justin Verlander, tweeted his support, saying:
"Couldn't be more proud of Kate Upton. I know this difficult decision to tell her story is to empower others in similar situations, and also to encourage those who witness this behavior to speak out to create change. That is what the #MeToo movement is all about! #ThankYouKate."
"I had to go through this moment where I was like, 'That's not my fault. That's his fault.' That is his way of acting, and I had to empower myself again," Upton said of Marciano.
Watch the video above to see Upton's full interview and what she says pushed her to come forward.
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