Story highlights Comey will testify Thursday

GOP lawmakers are worried Trump will tweet during the hearing about Comey's testimony

Washington (CNN) As Former FBI Director James Comey prepares to testify before the Senate Thursday, Republican lawmakers have a message for President Donald Trump: Turn off the TV and hide your phone.

"Oh, I wish he'd do something else. It's not going to change the testimony," said Senate Intelligence Committee Chairman Richard Burr, a Republican from North Carolina, who will chair the Comey hearing.

Comey's opening statement, released Wednesday, revealed he will cast the commander-in-chief in a harsh light. Comey is expected to detail how Trump asked him to let an investigation into former national security adviser Michael Flynn go, as well as how Trump demanded loyalty from the former FBI director.

Many Republicans are anxious to hear from Comey, and fear Trump's tweeting or public comments could create even more of a spectacle out of what is already expected to be a blockbuster day on Capitol Hill.

"There's been some speculation that he would live tweet," said Sen. Jeff Flake of Arizona. "I would argue that's not a good idea. I think anybody would tell him that."

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