Kellyanne Conway slammed John Dean's credibility Monday morning hours before he is scheduled to testify in the House on the Mueller report.

Conway criticized the House Democrats' decision to hold a hearing with the former Nixon White House counsel while blocking her own attempts to brief Congress on the impact of drug crisis legislation passed last year.

"I work on the opioid and drug crisis in the White House, as you know. We had every single Democrat vote on the legislation last year. That was wonderful," Conway told Fox News on Monday morning. "This week, my office is trying to get me up on Capitol Hill for an annual briefing of the senators and the House members. We can’t get a room in the House."

"They are using it for John Dean’s makeup room," Fox host Brian Kilmeade quipped.

"It's really something. I've never been disbarred. I passed four state bars, never been disbarred. Never went to jail for obstruction of justice and don't plan on it, but they are picking lawyers from TV now," Conway responded. "Remember, he also tried to derail Brett Kavanaugh's nomination. He’s not a credible person."

Dean is scheduled to testify in front of the House Judiciary Committee at 2 p.m.