A judge has ordered an FBI agent to wear a disguise while testifying against an accused ISIS sympathizer.

Federal prosecutors had asked the courtroom be sealed to the public for the witness' testimony in Fabjan Alameti's upcoming trial for the safety of the informant.

U.S. District Judge Dana Christensen ruled that a disguise consisting of a wig or hat, fake glasses, and fake facial hair, is a reasonable way to protect the FBI informant's identity while still allowing a public trail.

Federal agents say Alameti talked about joining ISIS, and attacking random American civilians in revenge for shootings at two mosques earlier this year in Christchurch, New Zealand, which left 50 people dead.

Read more: ABC Fox Montana