WASHINGTON — (CNN) Top Hillary Clinton aide Huma Abedin will be interviewed Friday by the House Benghazi Committee in a closed session in the Capitol, according to a GOP source familiar with the committee’s activities.

The appearance comes six days before her boss, the former secretary of state and current Democratic presidential candidate, delivers much-anticipated public testimony before the committee.

The Republican-led special panel is investigating the 2012 attacks on U.S. government posts in Libya that killed four Americans, including U.S. Ambassador Christopher Stevens.

But recently it has turned much of its attention to Clinton’s use of a private, unsecured email server while she was the nation’s top diplomat, a revelation that polls show have hurt her standing with some voters.

Abedin is a high-profile senior aide to Clinton, seen regularly at her side for many years. Her interview is not a formal deposition, according to the committee source, and is expected to be conducted largely by committee staff members because lawmakers are on recess this week.

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