Singer Lady Gaga has been the victim of a targeted attack on her Twitter and Facebook accounts.
Multiple messages, seemingly from the singer, offered "free iPad2's to each one of you".
Attached links directed more than 100,000 of her followers to a site requesting personal details, possibly as part of a phishing scam.
The 25-year-old, Twitter's most followed user, later tweeted: "Phew. The hacking is over!"
Her Facebook page, which is "liked" by more than 45 million fans, had earlier posted the message: "Lady Gaga's new iPad comes out in 3 days!
"So for the next 72 hours we will be hosting a massive giveaway to all the Mother Monster fans. Sign up and receive your special Lady Gaga edition iPad in time for the Holidays! For contest rules and registration visit the link below."
This was followed later by a tweet saying: "Monsters, I'm giving away FREE ipad2's to each one of you in the spirit of the holidays :)"
The singer often refers to her fans as "monsters", suggesting the hack was specifically targeted at the singer - rather than a more general phishing attack often seen on social networking sites.
Phishing attacks typically trick users into believing they are signing in to a legitimate website, but instead illegally gather personal data which can then be used to gain access to private accounts such as email and banking.
The offending messages have now been removed, but web statistics show more than 100,000 of her fans followed the links.
The Grammy award winner's management would not comment on the attack.
Security researcher Graham Cluley noted that other artists, such as Nelly Furtado and Maroon 5, seemed to have come under similar targeting.
"It is, of course, particularly important that the administrators of popular Facebook pages - which can have many millions of fans - take security seriously to minimise the possibilities of passing a scam on," Mr Cluley wrote.
"If nothing else, it's not terribly good for the brand to annoy your fans or to put them at risk."