By Paul Thompson and Paul Bentley for the Daily Mail and Rob Waugh

Scandal: Scarlett Johansson, seen here in 2006, has called in the FBI after nude photos of her leaked online after they were stolen by a hacker

Scarlett Johansson has admitted that she took naked photographs of herself which were leaked online.

The 26-year-old Lost In Translation star, who has never appeared fully nude in her movies, has been left humiliated after the explicit pictures were published on a website yesterday.

The FBI has, meanwhile, been called in to investigate how the private photographs were hacked from her mobile phone – and it emerged today that it is closing in on the suspected hacker.

Law enforcement sources told TMZ authorities are ‘honing in’ on the criminal gang, with the identity of one of the ringleaders known to the FBI.

Johansson is the latest victim of the phone-hacking ring thought to be responsible for stealing naked photos and videos from at least 50 female Hollywood celebrities.

Johansson’s lawyer today issued a statement making it clear that his client took the explicit pictures.

One of the photographs shows her posing seductively with her top off, while in another her bare behind is visible in a mirror.

The photographs show wallpaper in the background which matches the design in previously seen pictures from inside her bedroom in Los Angeles.

While parts of her body have been exposed for her movie roles, she has never before been seen completely naked.

‘The highly personal and private photographs at issue capture our client self-posing in her own home in a state of undress and/or topless,’ the statement, from lawyer Marty Singer, read.

He also threatened to sue any media outlet which publishes the pictures under copyright laws – the fact that Johansson holds the rights confirms that she took the pictures and that they are authentic.

Authorities also today confirmed it is looking into the case.

‘The FBI is investigating a person or group responsible for a series of cyber intrusions of high-profile figures,’ FBI spokeswoman Laura Eimiller said.

‘This would include many devices – could mean a computer, desktop, laptop, iPad, cell phone… intrusions into personal online accounts too.’

Other stars reportedly targeted  include actresses Jessica Alba, Vanessa Hudgens, Selena Gomez and Miley Cyrus, as well as singer Christina Aguilera.

Investigation: The actress, pictured here in a campaign for Mango, was named earlier this year as one of the 50 victims who had their cell phones or emails compromised by a hacking gang

Distinctive: The wallpaper shown in the background of the nude pictures appears to match the design on the walls in Scarlett’s bedroom, seen here

HOW HACKERS CAN STEAL PICTURES FROM YOUR PHONE

Miss Johnasson is likely to have had the photographs stolen by hackers after she tried to email them, experts explained.

Other possibilities include hackers infecting her phone with malicious software, or taking the data from a computer paired to the phone via a virus.

Graham Cluley, senior technology consultant at security firm Sophos, told the BBC: ‘My guess is that, even if these photos were taken on Scarlett Johansson’s phone, she would then maybe have emailed them to somebody.

‘Then, either their email got hacked or they were in her sent folder in her online email account – that would be the most natural way.’

Orla Cox, Norton Internet Security Expert, added: ‘Smartphones such as iPhones are only as secure as you make them. If you don’t have a passcode, and leave it lying it around, people can easily steal directly from you, simply by picking it up and sending pictures direct from the phone.

‘Even if you have  a passcode, a determined hacker can often guess – many people use simple combinations such as 1,2,3,4 or repeated digits.

Hackers may have attacked the PC the iPhone was ‘paired’ with and stolen pictures that way.

Sophisticated modern hackers do their research on targets and create tailor-made attacks which play on the victim’s personal interests.

These type of hackers tend to be organised criminals who use socially-engineered deceptions to breach computer and smart phone security.

Socially engineered attacks use details culled from sites such as Facebook to ‘trick’ the user into installing software – sending emails that appear to be from a friend, but that install malicious software that let them ‘control’ a victim’s PC.

If any lesson is learned, it is that if you don’t want explicit pictures spread online, don’t take them and send them around in the first place.

Gossip sites in America have been speculating as to whether the photographs were meant for her ex-husband, actor Ryan Reynolds, or any of the men she has dated since the break-up, who include fellow Hollywood A-lister Sean Penn.

Bloggers have linked the leaks to a hacking group called Anonymous that has boasted of targeting celebrities.

Black Swan star Mila Kunis was also named as a target, with hackers allegedly uncovering picture of a shirtless and ‘seductive’ Justin Timberlake on her phone.

One image is said to show Timberlake wearing pink underwear on his head while there is another reported to be a separate explicit shot of an unidentified male.

A fourth image is said to show Kunis in a bath, covered by the tub from the neck down.

Kunis and Timberlake, co-stars in the film Friends With Benefits, have long denied rumours of an off-screen romance.

It is not clear if the Johansson and Kunis incidents are related.

Celebrity website TMZ.com  said Johansson had called in the FBI as a ‘criminal act’ had been committed.

‘The FBI is aware of the alleged hacking incident and is looking into it,’ an FBI official told FoxNews.com.

Now the star has threatened to sue anyone who publishes the nude photos.

Her lawyer Marty Singer has now written to various websites, warning of legal action.

The photographs are currently still being shown on buzzfeed and Daily Gossip, among other sites.

‘If you fail to comply, you will be acting at your own peril. Please govern yourselves accordingly,’ the letter states.

Johansson was named earlier this year as one of 50 victims who had their mobile phones or emails compromised by a hacking gang.

High School Musical star Vanessa Hudgens met with the FBI to discuss the hacking of her Gmail account after photos of her kissing another woman were leaked online.

Sources connected to Johansson told TMZ the actress had called in the FBI to investigate the leak.

She is currently filming the super-hero film The Avengers with Captain America star Chris Evans and Hollywood A-lister Robert Downey Jr.

A spokesman for Johansson refused to comment.

Target: Hackers allegedly found shirtless pictures of Justin Timberlake after tapping into Mila Kunis’ phone

Hacked: Miley Cyrus and Vanessa Hudgens are other alleged victims of the hackers