Ryan Seacrest says his stalker's efforts to get close to him are 'extremely frightening.' (Christ Pizzello/Associated Press)

 American Idol host Ryan Seacrest has been granted a restraining order against a man who was arrested outside the TV personality's workplace while carrying a knife.

Lawyers for Seacrest got the order from a Los Angeles judge on Friday after Chidi Benjamin Uzomah Jr. was detained at the E! Entertainment Television headquarters the same day.

Records show the 25-year-old man is already on probation for a previous incident involving Seacrest.

Last month, Uzomah pleaded guilty to three misdemeanours, including carrying a switchblade knife as well as assault and battery. That was after he attacked one of Seacrest's bodyguards outside an event.

Uzomah was sentenced to 15 days in jail and three years probation.

"His aggressive and violent efforts to come into physical contact with me are extremely frightening to me," Seacrest wrote in a statement to the court.

"They have jeopardized not only my personal safety, but also the safety and well-being of those around me."

Security guards immediately held Uzomah when he showed up at E!'s offices because they recognized him from photos given to them after the last incident, said the E! website.

A hearing on whether to grant a three-year stay-away order against Uzomah will be held on Nov. 17.

With files from The Associated Press