Mila Kunis is the latest Hollywood A-lister to be the victim of a cell phone photo hack -- but the prime suspect, Hollywood Leaks, has not claimed responsibility.

An unidentified person sent an email to Perez Hilton on Wednesday, offering to sell compromising photos of Justin Timberlake that he sent to his Friends with Benefits costar.

I have 3 pictures of Justin Timberlake that were sent to Mila Kunis, the seller wrote.

In one of the pics he has Mila Kunis pink panties wearing over his head and in the second pic he poses in a bed. In another one he sent her a picture of his penis, unfortunately without his face there. I can send samples of them if you are interested.

And I know the story of Mila Kunis and her former boyfriend Mack Kulkin in addition to their broke up [sic]. Get at me!!

Perez Hilton warned celebrities to delete all of their naked cell phone photos.

Earlier Wednesday, naked self-portraits of actress Scarlett Johansson began making the rounds on Twitter and other Web sites. While the actress is in bed in one of the photos, she is not taking the invasion lying down: Johansson has reportedly enlisted the FBI to investigate the hacking.

The FBI is investigating a person or group responsible for a series of cyber intrusions of high profile figures, FBI spokeswoman Laura Eimiller told E! News. This would include many devices-could mean a computer, desktop, laptop, iPad, cell phone...intrusions into personal online accounts too.

The E! News report did not indicate whether the group in question is Hollywood Leaks, who claimed responsibility for hacking the phone of Dancing With the Stars talent Julianne Hough and circulating photos of the star in late August.

The group explained its mission to Gawker in August: We're simply here to facilitate the free flow of information from a place which was previously overlooked, Hollywood, an unidentified representative wrote in an email, prompting Gawker to tag them Wikileaks to the Stars.

But the Hollywood Leaks Twitter feed has been silent since September 8.

The group claims to be an offshoot of the Anonymous hacking ring, and the two groups share the same creepy tagline: WE DO NOT FORGIVE WE DO NOT FORGET EXPECT US.