A 4chan user claims to have released nude photos of several female celebrities in a major hacking.

The hacker said that he or she leaked photos of Jennifer Lawrence, Kate Upton, and a host of other stars.

A rep for J.Law confirmed that the images, allegedly stolen from her iCloud account, are real.

"This is a flagrant violation of privacy," the spokesperson told HuffPost. "The authorities have been contacted and will prosecute anyone who posts the stolen photos of Jennifer Lawrence.

The Los Angeles Police Department told HuffPost that they have "no knowledge" of the hacking "at this time." In a statement on Monday the FBI said, "The FBI is aware of the allegations concerning computer intrusions and the unlawful release of material involving high profile individuals, and is addressing the matter. Any further comment would be inappropriate at this time." Apple did not return a request for comment.

The hacker claims to have more NSFW pics as well as videos. The user offered to release more media in exchange for money.

Victoria Justice, who was also targeted in the hack, tweeted that the photos aren't real.

"These so called nudes of me are FAKE people," she said. "Let me nip this in the bud right now. *pun intended*"

A rep for Ariana Grande told BuzzFeed that the photos of her are "completely fake."

Horror movie actress Mary Elizabeth Winstead lashed out at the hacker on Twitter.

"To those of you looking at photos I took with my husband years ago in the privacy of our home, hope you feel great about yourselves," she said. "Knowing those photos were deleted long ago, I can only imagine the creepy effort that went into this. Feeling for everyone who got hacked."

UPDATE: Kate Upton's attorney told the Huffington Post in a statement, "This is obviously an outrageous violation of our client Kate Upton's privacy. We intend to pursue anyone disseminating or duplicating these illegally obtained images to the fullest extent possible."