President Donald Trump wished his former national security adviser Michael Flynn "good luck" hours before he is sentenced in federal court for lying to the FBI, adding that he is interested in hearing what Flynn says before a judge.

"Good luck today in court to General Michael Flynn," Trump tweeted early Tuesday. "Will be interesting to see what he has to say, despite tremendous pressure being put on him, about Russian Collusion in our great and, obviously, highly successful political campaign. There was no Collusion!"

Flynn, a retired Army lieutenant general, is set to find out whether he will spend any time in prison when he appears before U.S. District Judge Emmet Sullivan on Tuesday morning in U.S. District Court in Washington D.C. Flynn pleaded guilty last year to lying to the FBI about his contacts with then-Russian ambassador to the U.S. Sergey Kislyak.

Flynn has since offered his cooperation to special counsel Robert Mueller, who is investigating Russian interference in the 2016 presidential election and whether the Trump campaign colluded with Russian officials.

The former national security adviser, who lasted weeks in the job, may not serve prison time, as Mueller's prosecutors wrote in a sentencing memo to the judge last week that Flynn provided his team with "substantial assistance," adding that he should receive little to no prison time.

At the judge's request, the special counsel's office on Monday evening released a redacted version of the FBI's interview notes with Flynn. Known as a "302" document, the filing detailed the Jan. 24, 2017 conversation between Flynn and FBI agents.

That discussion, as the notes showed, centered around Flynn's conversations with Kislyak during the transition period after the 2016 election. Specifically, Flynn was asked at length about whether he discussed with Kislyak a UN vote on Israeli settlements the Obama administration abstained from and the sanctions placed on Russia in response to alleged election interference just prior to Trump taking office.

Flynn said he had a closed-door meeting with Kislyak following the election, but the details on that are redacted. Flynn said the purpose of his frequent communication with Kislyak, whom he exchanged multiple phone calls and text messages with during the transition, was to improve ties with Russia so the two nations could better fight terrorism together.

Sullivan ordered the document be made public after Flynn's attorneys suggested in a sentencing memo that the FBI agents may have acted improperly in their questioning of Flynn.