You won't find them lurking around Westminster Abbey and they definitely didn't receive an invite in the mail, but these unwanted guests are trying to crash next week's royal wedding.
Cybercriminals looking to cash in on Prince William and Catherine Middleton's big day have already begun targeting Australian internet users, hiding viruses and malicious software within emails falsely claiming to be royally relevant.
Internet security group Norton warned wedding watchers to be alert for online spam emails or dodgy websites promising juicy royal gossip, such as details of the wedding dress or photos of Prince William's bachelor party.
It's found that after television, the most common place for Australians to seek information about the April 29 wedding is online.
Three times as many people are expected to follow the event online as in newspapers, five times as many than in magazines and ten times as much as those over radio, Norton's research shows.
But many people aren't clear about the risks of running into fake sites, don't have internet security software on laptops or other adequate protection to surf the web.
"Potentially one in five Australians who plan on following the royal wedding are at risk of becoming a victim of cybercrime," Norton said in its report.
Internet usage spikes in the lead up to major international events and cybercrims began circulating viruses masked as leaked footage, scandalous images or other intriguing content as recently as March.
Norton said it's already found scams and examples of search engine poisoning for search such as "Royal Wedding Invitations", "Official Royal Wedding Merchandise", "Kate's Wedding Diet" and spam emails relating to copies of the royal ring.
"Where there are crowds, there will likely be cybercriminal wedding crashers who play on this zealous devotion, making people susceptible to online scams," Norton said.
It's advising people to think before they click, avoid clicking on unfamiliar sites and use security software on their computers.