President Trump’s "cyber czar," ex-New York mayor Rudy Giuliani, has joined the defense team of a gold trader who is under federal indictment for fraud, money laundering and evading sanctions on Iran, and who has ties to Turkish President Recep Erdogan.

Reza Zarrab, 33, was arrested March 19 in Florida. He‘s accused of ducking sanctions by moving hundreds of millions of dollars for the Iranian government and Iranian firms via offshore entities and bank accounts.

Prosecutor Joon Kim sent a letter notifying the judge in Zarrab’s case that Giuliani had joined the defense, and that Zarrab had also hired ex-U.S. Attorney General Michael Mukasey. Kim said he was "advis[ing] the Court of potential conflicts of interest," since Giuliani and Mukasey’s firms also represent some banks Zarrab used in transactions.

Erdogan defended Zarrab when the dual Turkish-Iranian citizen was fingered in a 2013 Turkish corruption scandal that also implicated Erdogan associates. The Turkish leader called Zarrab, who had given his wife’s charity $4.5 million, a philanthropist. All charges against Zarrab and Erdogan’s pals were dropped.

Zarrab’s lead attorney, Ben Brafman, told NBC News he would remain as lead counsel, and that neither Giuliani, Mukasey nor their firms would appear in court.