(CNN) The White House is asserting immunity for President Donald Trump's long-time confidant Hope Hicks from testifying in the House Judiciary Committee about her time at the White House, setting up a showdown with Democrats when Hicks appears behind closed doors on Wednesday.

But Democrats' on the House Judiciary Committee are also planning to press Hicks on events that occurred before Trump took office, including her knowledge of the hush-money scheme to silence Trump's extramarital affairs in the run-up to the 2016 presidential election, according to a committee aide.

The anticipated line of questioning signals renewed interest on Capitol Hill over the President being implicated in felonies committed by former Trump fixer Michael Cohen, after the panel has been mostly focused until now over the allegations detailed in special counsel Robert Mueller's report on obstruction of justice.

Hicks is the first member of Trump's inner circle to appear before the House Judiciary Committee, which is undertaking its own investigation into possible obstruction of justice, corruption and abuse of power as House Democrats wrestle with whether to start an impeachment inquiry. But White House counsel Pat Cipollone wrote to the committee Tuesday ahead of Hick's appearance to argue that she is "absolutely immune" from being compelled to answer questions about her time as a senior adviser to the President.

"Because of this constitutional immunity, and in order to protect the prerogatives of the Office of President, the President has directed Ms. Hicks not to answer questions before the Committee relating to the time of her services as a senior adviser to the President," Cipollone wrote, adding that Hicks previously testified before the House and Senate Intelligence committees under similar circumstances.

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