Attorney and frequent Fox News guest Alan Dershowitz criticized host Sean Hannity on Monday for not disclosing his relationship with Michael Cohen, President Trump's personal attorney, during his frequent discussions about Cohen in recent weeks.

Dershowitz, who has defended Trump amid his legal woes, was brought on to discuss former FBI Director James Comey's Sunday night interview on ABC News's "20/20," but first addressed the Monday revelation that Hannity is Cohen's previously unnamed client.

"I really think you should have disclosed your relationship with Cohen," Dershowitz said, calling it a "complicated situation."

"It was minimal," Hannity responded.

"I understand that, and you should've said that," Dershowitz, an opinion contributor for The Hill, replied. "You were in a tough position because, A, you had to talk about Cohen, and, B, you didn't want the fact hat you had spoken with him to be revealed."

"I have the right to privacy," Hannity interjected. "It was such a minor relationship."

"You should have said that," Dershowitz said.

Hannity was revealed to be Cohen's client during a hearing Monday afternoon related to last week's FBI raids of Cohen's office, hotel room and home. Cohen's attorney only shared Hannity's identity after a judge ordered him to.

Hannity is a staunch ally of Trump's and frequently defends the president on his Fox News show. He was fiercely critical of last week's raids, using it as a launching point to attack special counsel Robert Mueller's probe into Russian meddling in the 2016 presidential election.

Two Democratic lawmakers on Monday called on Fox News to take Hannity off the air over the undisclosed relationship, saying Hannity covering the Cohen story represents a conflict of interest.

Hannity downplayed his connection to Cohen shortly after the news broke, asserting that Cohen had never formally represented him in legal proceedings.

"I have occasionally had brief discussions with him about legal questions about which I wanted his input and perspective," Hannity tweeted, adding that those conversations "dealt almost exclusively about real estate."