Karwai Tang/WireImageThe website belonging to the lawyer of several high-profile celebrities, such as Lady Gaga, Robert De Niro, Elton John and many others was hit by a cyberattack, where hackers are now holding his client’s sensitive and personal information hostage.

Page Six reports that the hackers have instructed attorney Allen Grubman to pay a $21 million ransom or the 756 gigabytes of stolen information will be leaked to the public.  As of Wednesday, the Grubman Shire Meiselas & Sacks website remains down.

To pressure Grubman, the hackers have already released an alleged contract belonging to Madonna and are now promising to dump all of his clients’ contact information and personal emails.  The hackers also allegedly have in their possession his clients’ endorsement deals, settlements and contracts, as well.

Page Six reports that the FBI is investigating the incident.  It is believed that the hackers are going by the name REvil or Sodinokibi.

The firm confirmed in a statement on Tuesday, “We can confirm that we’ve been victimized by a cyberattack. We have notified our clients and our staff. We have hired the world’s experts who specialize in this area, and we are working around the clock to address these matters.”

It’s been reported that Grubman has not met the hackers’ demands and is not willing to negotiate.

The attorney represents some of Hollywood’s biggest stars, such as Sofia Vergara, Robert De Niro, Priyanka Chopra and athletes like Lebron James.

On the music side, he represents major acts such as Rod Stewart, Barbra Streisand, U2, Drake, Lil Nas X and Barry Manilow.

A spokesperson for Grubman tells Page Six that their firm is just the latest victim of “this global extortion scheme,” adding that the hackers have targeted other high-profile victims such as HBO and the Texas court system.

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