Former FBI Director James Comey will appear before the Senate Intelligence Committee next Thursday in what will be his first public appearance since explosive reports that Comey authored memos claiming President Donald Trump urged him to drop an investigation into a White House aide.

The formal subject of the hearing, slated to begin at 10 a.m., is Russian efforts to interfere in the 2016 presidential election. And the former FBI head is likely to get questions about what exactly Trump told him about the investigation into former National Security Adviser Michael Flynn.

It’s unclear, however, just how much Comey will be able to reveal in the public portion of the hearing. Special Counsel Robert Mueller had to approve the Comey appearance, but some areas of discussion may be off topic out of concerns it could impede an ongoing investigation.

Comey allies have told NBC News he is eager to tell his story after abruptly being fired by Trump last month. Trump cited the Russia investigation as part of his reasoning behind dismissing Comey, leading Democrats, and some Republicans, to call for an investigation into whether the president obstructed justice.

White House press secretary Sean Spicer referred questions about Comey’s upcoming testimony to Trump’s outside counsel while speaking to reporters on Wednesday. Trump officials have denied accusations that the president attempted to thwart the investigation.

Comey’s memo details how Trump told him "I hope you can see your way clear to letting this go, to letting Flynn go," a source close to Comey told NBC News. Flynn resigned in February after misleading senior White House officials about his interactions with Russia’s ambassador to the United States.

The FBI has so far resisted calls from Congress to turn over the memos, since they are relevant to a criminal investigation.

Comey will brief senators in a closed door session following his opening hearing.