Transcript for Mark Zuckerberg prepares to testify on Capitol Hill
Let's head over to Capitol Hill. The CEO of FaceBook Mark Zuckerberg is in the hot seat today testifying before congress it is news and Mary Bruce joins us now live from Capitol Hill. Mary have to be very unusual for god it's used to wearing a T shirt to work every single day who expect an apology from him on that big deep reach that happen. Richard you are gonna get an apology and I think you're gonna see him in a suit once again it's up here yesterday meeting with lawmakers had treated out that the entered T -- for something a little bit or perhaps appropriate to Capitol Hill now let me show you the room here because. This is where Zuckerberg will be sitting in just a few hours making his first appearance before lawmakers as he runs through what is essentially the congressional gauntlet here. This is a very rare saying you can see everyone here's getting spat at photographers are setting their cameras at around. Getting a sense of the room here. But he's appearing before actually two committees in one hearing it's why you sees how many shares are expected to bring in. More chairs bring in more tables he's going to be good rail. By 44. Senators that is nearly half. Of the entire US senate that we'll have a chance to ask the tough questions of Zuckerberg lawmakers have been waiting a very long time for this. Remember he is someone who carefully controls his public appearances which media he talks to. Here he's going to have to answer these questions one way or another and they he's going to be pressed on not only issues user privacy of course Russian meddling in the election but also what steps he's willing to take going forward. What kind of oversight. He's willing to have. Two to ensure that Americans data is protected going forward. Alan the world has certainly watching I'm sure he knows it is there any inside and out yet prepare for this big day. He get he's been studying up in York times reports that he's actually be doing mock debates. When many of his advisors his legal team has been prepping him for how to answer these questions. Were led the reporting is that he's been told how to act. Humble how did not in Iraq how to respond when it when he's pushed really hard look he's not when he's known for his approach ability pact and owners watching Saturday Night Live last week and you saw he was mocked for it. Once again but we know from his prepared testimony that he's coming up here continuing this apology toward that he's been on. For the last several weeks he's going to say that ultimately the buck stops with him he says his company he runs it. He made mistakes and he's looking for ways to move forward Rachel. Are able ABC news's neighbors thank you so much for joining us and providing us with that preview of course we will have. Full coverage of that when that testimony starts with a spouse report right here on ABC news later this afternoon so be sure to stick around firm for that.
This transcript has been automatically generated and may not be 100% accurate.