"Former U.S. Attorney for the District of Columbia Joe diGenova will be joining our legal team later this week," Jay Sekulow, a counsel to the president, said in a statement. "I have worked with Joe for many years and have full confidence that he will be a great asset in our representation of the President."

The hiring was first reported by The New York Times, which wrote that diGenova is unlikely to take a lead role on the team, but that he would add an aggressive presence.

The president is increasingly signaling he intends to go in a different direction with his legal strategy, and this weekend began attacking by name special counsel Robert Mueller.

Trump's lawyers had previously advised him not to attack Mueller.

Adding diGenova suggests Trump wants to go more on the offensive, given diGenova's past statements arguing that investigations of Trump are meritless.

“Make no mistake about it: A group of FBI and DOJ people were trying to frame Donald Trump of a falsely created crime,” he said.

Over the weekend, Trump tweeted that the Mueller probe should "never have been started."

"There was no collusion and there was no crime. It was based on fraudulent activities and a Fake Dossier paid for by Crooked Hillary [Clinton] and the [Democratic National Committee], and improperly used in [Foreign Intelligence Surveillance Act] COURT for surveillance of my campaign. WITCH HUNT!" Trump tweeted.

On Monday, Trump again called the investigation a "witch hunt" and claimed it had "massive conflicts of interest."

Trump's lawyer John Dowd over the weekend also called on Deputy Attorney General Rod Rosenstein to shut down Mueller's Russia probe.

On Monday, White House spokesman Hogan Gidley said there are "no conversations or discussions about removing" Mueller. He also reiterated that there has been no collusion.

This story was updated at 2:39 p.m.