Web searches for Brad Pitt have been found to be the most likely to lead the user into dangerous online territory.

Security firm McAfee said that the film star's name is more likely to direct a user to malicious sites than any other celebrity's name.

Fans searching for Brad Pitt have nearly a one in five chance of encountering a potentially risky site, according to the research.

Around 18 per cent of searches lead to wallpapers, screen savers and photos that carry some sort of malware. Searching for Brad Pitt screensavers bumps the infection risk up to 50 per cent.

Beyoncé was rated the second most dangerous celebrity query. McAfee warned that searching for the singer's ringtones was particularly risky for users and could lead to malware infection and stolen personal information.

Third on the list was Justin Timberlake, whose various public romances have made him a hot target for searches and a prime lure for malware writers. Timberlake was followed by searches for Heidi Montag, Mariah Carey and Jessica Alba.

Rounding out the list of riskiest searches are Lindsey Lohan, Cameron Diaz, George Clooney and Angelina Jolie, who was the subject of a major malware attack earlier this year.

Jeff Green, senior vice president of product development at McAfee, said that popular culture and celebrity sites have become fertile breeding grounds for malware, and that users should be careful when looking for the latest gossip.

"Americans' obsession with celebrity lifestyles makes them an obvious target, " said Green. "We have to take precautions in casually navigating the web since many subtle sites may be rife with malware."