POLICE have charged a schoolboy as they escalate their investigation into a Facebook party invitation gone viral.

The 17-year-old boy allegedly hijacked a Facebook birthday party invitation originally posted by Chatswood schoolgirl Jess, which resulted in 214,000 people accepting the invitation to the party at her house on March 26, The Daily Telegraph reports.

The schoolgirl reported that the site had been hijacked to police yesterday.

T-shirts have gone on sale with the name and date of the 15-year-old Sydney schoolgirl who posted her "small house birthday party" on Facebook.

The Year 10 student originally intended to invite her grade only, but told her guests via the social networking site they could bring friends.

Within 24 hours, the party had more than 20,000 people listed as "attending", prompting the schoolgirl to send an unhappy message cancelling the party: "it's f***in off."

The invitation appeared to have been hijacked by members of the notorious chat group Anonymous, or viral prankster David Thorne, resulting in it going viral worldwide.

A number of the postings on her party invitation Facebook site were using the Anonymous symbol as their own.

Today, a website looking to cash in on Jess' s sudden popularity have made a T-shirt with her name and the date of her party. It costs $15.50.

On her invitation, Jess said she "didn't have enough time to invite everyone" and invited others to do it on her behalf: "(It's an) open house party as long as it doesn't get out of hand."

One guest posted on the party's wall: "That Corey Worthington kid has nothing on this", referring to the 500 guests who attended a now notorious house party in Melbourne after it was advertised on MySpace.

Jess's father, who asked that his name be withheld, said the invitation was "a complete hoax". "My girl is an innocent victim," he said.

Read more about the boy charged over Jess's Facebook party at The Daily Telegraph.