On the eve of what could be a blockbuster hearing with President Donald Trump's former personal lawyer, a GOP lawmaker who is a close ally of the President raised the specter of Republicans airing dirty personal laundry about Michael Cohen at a hearing on Wednesday, spurring accusations of witness intimidation.

"Do your wife & father-in-law know about your girlfiends?" Rep. Matt Gaetz (R-FL) said on Twitter in a post directly aimed at Cohen, who plead guilty late last year to campaign finance violations on behalf of President Trump, as well as lying to Congress.

In a speech later Tuesday evening on the House floor, Gaetz delivered another warning to Cohen.

"We will find out if there is anyone that Michael Cohen hasn't lied to," Gaetz said, as his office quickly posted the video of his speech.

"I guess it will be relevant for us to determine, does he lie to his own family?" Gaetz asked, even as he denied it was any effort at witness tampering.

"It's witness testing," the Florida Republican told reporters.  One note - Gaetz is not a member of the House Oversight Committee, and thus won't be present for the Cohen hearing.

But the message was certainly delivered.

Democrats swiftly denounced Gates, and accused him of witness intimidation.

“This tweet is despicable, even for a dimwitted and craven Trump sycophant,” said Rep. Jared Huffman (D-CA).

“This comment crosses the line professionally, ethically, and morally,” said Rep. Madeleine Dean (D-PA).  “This toxicity has no place in Congress.”

Gaetz - a favorite House member of the President's - has been involved with other more conservative GOP lawmakers in the House in trying to mount an aggressive defense of the President over the Russia investigation, mainly attacking the Mueller investigation, but in this case branching out to one of the cooperating witnesses.

"Giving a platform to Mr. Cohen is beneath the dignity of the Congress," said Rep. Jim Jordan (R-OH), who will lead the GOP questions for Cohen in the House Oversight Committee.

Asked about the comments from Gaetz, Oversight Chairman Rep. Elijah Cummings (D-MD) told reporters he wasn't worried about any GOP strategy to derail Cohen and his story.

"We have one job to do - it's in the Constitution, and we're going to do it," Cummings said bluntly to reporters just off the House floor.

As for Cohen, he said - and Senators confirmed - that the President's former lawyer admitted he had previously lied to lawmakers, but this time was on Capitol Hill to tell the truth.

"I really appreciate the opportunity that was given to me to clear the record, and tell the truth," Cohen said, without going into any specifics.

When Cohen testified last before the Senate Intelligence Committee in October of 2017, he told Senators that efforts by the Trump Organization to cut a deal for a Trump Tower project in Moscow had stopped in January of 2016, and that there were no contacts made with any Russian officials during the campaign.

In his guilty plea late last year, Cohen acknowledged all of that was a lie - a cover story meant to protect the President from the Russia investigation.