Facebook founder Mark Zuckerberg will testify at a congressional hearing Tuesday to explain why at least 87 million Americans had their information mined without their consent by a political research firm.

>>See live updates from the hearing below.

Zuckerberg is scheduled to testify at two hearings this week. Tuesday, he will appear before a joint session of the Senate Committee on the Judiciary and the Commerce, Science, and Transportation Committee. On Wednesday, he will answer questions from the House Energy and Commerce Committee.

There are 44 senators on the Senate Judiciary and Commerce committees who Zuckerberg will be testifying before Tuesday, and each is allotted four minutes for questions and answers.

Look for Zuckerberg to be pressed on data privacy following the revelation that the political research firm Cambridge Analytica was able to gain access to information about millions of Facebook users.

He will also likely be grilled on how Russian interests were able to use the social media site to interfere with the 2016 U.S. presidential election.

His opening prepared statement has already been released.

Zuckerberg will likely also be answering questions about Facebook's retention of data from its Messenger app and bulk harvesting of public profiles on the site.

Zuckerberg’s testimony is set to begin at 2:15 p.m. ET Tuesday. Check back here beginning at 1:45 p.m. ET for live updates from his testimony.

Live updates