Donald Trump Jr. is expected to speak to the Senate judiciary committee behind closed doors Thursday, two Senate sources tell CNN.

Trump Jr. has already provided the committee with documents. One source described Trump Jr. as being cooperative with the committee.

His involvement in a Trump Tower meeting in June 2016 with a Russian lawyer who promised damaging information about Hillary Clinton has been of great interest to the committee.

The Washington Post was first to report Trump's planned appearance.

The Senate intelligence committee has led the bulk of Senate inquiries into the Russian interference in the 2016 election and possible collusion with the Trump campaign. But the Senate judiciary committee has ramped up its own inquiries in recent months.