London - Nude photographs of Jennifer Lawrence - as well as images that purportedly show more than 100 celebrities - have leaked online.
The phone photos were reportedly obtained through Apple's iCloud service before they were published on 4chan, the image-sharing forum.
A list of the alleged victims - 101 in total - reportedly posted by the hacker has also appeared. Most of those named have not seen their photographs leaked by the hacker.
A spokesperson for Oscar winner Lawrence confirmed to MailOnline the photos of her are genuine.
“This is a flagrant violation of privacy. The authorities have been contacted and will prosecute anyone who posts the stolen photos of Jennifer Lawrence,” the emailed statement read.
The hacker wrote on Sunday he or she is accepting Paypal donations for a video which allegedly shows Lawrence performing a sex act.
The hacker also wrote, “I know no one will believe me, but i have a short lawrence video.
“Is way too short, a little over 2 minutes and you only get to see her boobs
“Anyways, if somebody wants it let me know how i can upload it anonymously (i dont want the FBI over me, and you dont wanna know how I got this video.)”
‘Jennifer Lawrence’ became a Twitter trend on Sunday afternoon.
A spokesman for Kate Upton sent MailOnline a statement from her attorney, Lawrence Shire, about the leaked photos.
“This is obviously an outrageous violation of our client Kate Upton's privacy,” the statement said. “We intend to pursue anyone disseminating or duplicating these illegally obtained images to the fullest extent possible.”
Actress Mary Elizabeth Winstead, who confirmed she was a hacking victim, wrote 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 also expressed sympathy for others, tweeting: “Knowing those photos were deleted long ago, I can only imagine the creepy effort that went into this. Feeling for everyone who got hacked.”
Winstead implied she was facing difficulties on Twitter on Sunday, when she tweeted 'Great day for the block button!'
Twitter is shutting down accounts that are disseminating the pictures.
In response to a request for comment from MailOnline, a Twitter spokesman said: “We do not comment on individual accounts, for privacy and security reasons,” and referred MailOnline to the company's content boundaries web page.
Photographs that allegedly show Kaley Cuoco-Sweeting, Lea Michele, Brie Larson, Kirsten Dunst, Becca Tobin, Hope Solo, Teresa Palmer, Krysten Ritter, McKayla Maroney, Jessica Brown-Findlay, Ali Michael, and Yvonne Strahovski appeared online.
Some of the women named as alleged victims - but who have not had any of their nude photographs leaked - include Aubrey Plaza, Candice Swanepoel, Cara Delevingne, Cat Deeley, Hillary Duff, Kelly Brook, Michelle Keegan, Selena Gomez, Rihanna and Vanessa Hudgens.
A spokesman for Keegan, the former Coronation Street actress, denied she had been targeted.
A rep for Keke Palmer - who was mentioned on the list but whose photographs were not leaked - told MailOnline 'Obviously there is no truth to this list and no nude photos of Ms. Palmer.'
Model Gabi Grecko - also named on the list but whose photographs have not been published - told Daily Mail Australia: 'I feel like anything I didn't release myself that was accessed without my permission is shameful.'
“Some people are very private and maybe hugely affected and feel violated because of this. There have also been many suicides connected to non consented photos being released.”
Not all of the nude photographs are genuine, however.
A spokesman for Ariana Grande told MailOnline photos that claim to show her are fake.
Similarly, Nickelodeon star Victoria Justice wrote on Twitter that her image was faked.
She tweeted, “These so called nudes of me are FAKE people. Let me nip this in the bud right now. *pun intended.*”
Justice retweeted a user named @JusticeCosgrove, who wrote “GUYD [sic] WE ARE SO STUPID THE VICTORIA JUSTICE NUDES ARE FAKE, LOOK. CLEARLY AN OLD PICTURE OF HER EDITED & FLIPPED.”
@JusticeCosgrove included a selfie of Justice, alongside a portion of her face that was seen in one of the “leaked” photographs.
Seth Rogen criticized the hacker on Twitter, writing “Posting pics hacked from a cellphone is really no different than selling stolen merchandise.”
“I obviously am not comparing women to merchandise. Just legally speaking, it shouldn't be tolerated to repost stolen pics,” Rogen also tweeted. - Daily Mail