Host of "Special Report" Bret Baier said Tuesday he expects former Special Counsel Robert Mueller will stick to his script on Wednesday when he testifies before two House panels to discuss the findings of the Russia investigation.

Baier said on "Daily Briefing" that the proceedings could get "messy" and he was worried it would turn into "an opportunity to be in the spotlight for lawmakers to make a campaign commercial for back home."

As the much-anticipated hearing approaches, Democrats and Republicans are gearing up to hear from Mueller directly, many preparing to ask for clarifications on the 400-plus page report.

Mueller previously stated that he would stick strictly to the report and that he would offer no additional information.

A Justice Department official told Mueller that his upcoming testimony "must remain within the boundaries" of the public, redacted version of his report, in a letter obtained by Fox News on Monday evening.

Attorney General William Barr later stated that this letter was requested by Mueller himself, reiterating his intentions to remain within the confines of the publically available report.

NADLER: SUBSTANTIAL EVIDENCE PRESIDENT TRUMP 'GUILTY OF HIGH CRIMES AND MISDEMEANORS' CONTAINED IN MUELLER REPORT

Democrats plan to use the forum to spotlight allegations against Trump of obstruction of justice, while Republicans are homing in on questions about the early stages of the investigation, Baier explained.

"Judging by his press conference after the report came out, talking to reporters saying that he essentially is going to say what's in the report. So Democrats may try and get more out of him but he may just say, 'well let’s look at page 402.' And that’s all they're going to get," Baier said Monday on "Outnumbered Overtime."

BRET BAIER: MUELLER HEARING COULD BACKFIRE ON DEMOCRATS

House Speaker Nancy Pelosi laid out a plan Tuesday making clear she plans to take this matter into the fall of 2019.

CLICK HERE TO GET THE FOX NEWS APP

"It's about continuing this pitch. They believe that they can try to instruct the American people on the road to impeachment and it's a dangerous road because the American people at some point -- if push comes to shove and the case is not made, will make a determination as you head into the election, how important that is," said Baier.

The hearing will begin at 8 am Wednesday and will include special coverage from Fox News.