WASHINGTON — Hope Hicks, one of President Trump’s closest former campaign and White House aides, has agreed to participate next week in a transcribed interview with the House Judiciary Committee on topics stemming from the special counsel’s investigation, the panel’s chairman said on Wednesday.

The hearing will be the first time that an aide to Mr. Trump has taken the witness stand in the committee’s investigation into whether the president obstructed justice by trying to curtail inquiries into his campaign’s ties to Russia. It could theoretically kick-start Democrats’ efforts to build a case against Mr. Trump.

But there is no guarantee that Ms. Hicks will be forthcoming. Given Mr. Trump’s claims of executive privilege over the blacked-out portions of the report by the special counsel, Robert S. Mueller III, and the evidence underlying it, Ms. Hicks could choose to try to use the president’s objections as a shield to fend off questions she does not want to answer about her time at the White House.

Representative Jerrold Nadler of New York, the committee’s chairman, hinted at that possibility on Wednesday. In a statement, he reiterated Democrats’ views that Mr. Trump’s executive privilege assertion, made after the material in question was already shared with nongovernment lawyers and then Mr. Mueller’s investigators, would not stand up in court. Nor, they say, can it conceivably be applied to Ms. Hicks’s work on the campaign.