The White House informed the Democrat-controlled House Judiciary Committee that President Donald Trump had instructed his former aide Hope Hicks not to answer questions in a hearing scheduled for Wednesday.
"Ms. Hicks is absolutely immune from being compelled to testify before Congress with respect to matters occurring during her service as a senior adviser to the President," White House counsel Pat Cipollone said in a statement Tuesday.
Hicks was to testify before the Judiciary Committee in a closed session that would be released in a transcription form afterward.
"Because of this constitutional immunity, and in order to protect the prerogatives of the Office of the President, the President has directed Ms. Hicks not to answer questions before the Committee relating to the time of her service as a senior adviser to the President," Cipollone added.
Hicks was interviewed in the special counsel investigation into Russian election interference, and was quoted in the Mueller report that was released in redacted form.
Cipollone said in his letter that the White House might cite executive privilege to block Hicks' testimony.
"Much of Ms. Hicks's work during this period involved discussions with the President-elect and his staff relating to the decisions the President-elect would be making once he assumed office," Cipollone said.
"Accordingly, her responses to specific questions about this period would likely implicate executive branch confidentiality interests concerning that decisionmaking process," he added. "In order to preserve the President's ability to assert executive privilege over such information, a member of my office will attend Ms. Hicks's testimony on June 19."
Here's more on Hope Hicks' appointment with Congress:
House Democrats subpoena Hope Hicks, Annie Donaldson