Fox News gave Sean Hannity its “full support” on Tuesday, a day after the revelation that he was a client of Michael Cohen, Donald Trump’s embattled personal lawyer and a man the Fox star had vociferously defended on the news channel without disclosing the relationship.

Hannity, Fox’s biggest draw, was revealed to be a client of Cohen’s at a court hearing on Monday – an announcement that drew gasps from those in court.

Cohen’s offices, home and hotel were raided on 9 April by the United States attorney’s office in Manhattan as party of a criminal investigation into Trump’s lawyer.

The conservative commentator has dedicated much of his primetime opinion show to supporting Trump and called the raid on Cohen’s office part of “an all-hands-on-deck effort to totally malign, and if possible, impeach the president of the United States”.

He did not disclose his professional relationship with Cohen and fought over the weekend to keep his name out of court.

In a statement Fox News said: “While Fox News was unaware of Sean Hannity’s informal relationship with Michael Cohen and was surprised by the announcement in court yesterday, we have reviewed the matter and spoken to Sean and he continues to have our full support.”

Hannity has denied he was a client of Cohen’s and characterized his professional relationship with Cohen as trivial, stating that he asked him only for some small advice on property deals, never formally engaged him and “might have handed him 10 bucks”.

But the potential conflict of interest has sparked criticism even on his own show. On Monday the Harvard law professor Alan Dershowitz told Hannity: “I want to say that I really think that you should have disclosed your relationship with Cohen when you talked about him on this show.”