Donald Trump's former fixer has some sobering advice for Peter Navarro as he prepares for his first night behind bars: prison is "no cakewalk."

Trump's one-time attorney and fixer Michael Cohen — who notoriously served time behind bars for tax evasion, making perjurious statements and campaign finance violations — appeared on CNN's "Out Front" to warn the ex-president's former aide Navarro about what's in store.

Navarro reported to a prison in Miami Tuesday after being convicted of contempt of Congress for ignoring a subpoena to appear before the January 6 committee.

"Peter Navarro has no idea just how bad prison actually is," Cohen told anchor Erin Burnett. "And I'm speaking from experience; not once but twice when I was unconstitutionally remanded... It's terrible."

He noted that the compromise he and Navarro made to do Trump's bidding becomes all too real once you lose your freedom.

"Your whole life changes — and why is it changing? Because he's doing something for Donald Trump, a guy who's 100 miles away from him enjoying a Mar-a-Lago burger and a bunch of ice cream at his gilded club."

"I don't know what he's thinking."

ALSO READ: House Republican giggles over Hitler praise — and admits he never listens to Trump

Navarro, a staunch Trump supporter and Harvard-trained economist, walked into the federal corrections facility a day after Supreme Court Chief Justice John Roberts declined an 11th-hour bid to stall his four-month prison sentence pending appeal.

Navarro was punished for refusing to testify before Jan. 6 Committee members regarding his involvement in efforts to overturn the 2020 presidential election.

The 74-year-old Navarro stood before reporters before heading to FCI Miami, complaining that his incarceration dealt a “crippling blow to the constitutional separation of powers and executive privilege.”

Navarro maintains that he was insulated from testifying before Congress because of executive privilege, a confidentiality that is supposed to protect the president and top aides from disclosing particulars on making critical decisions.

Cohen said after he was released from his stint in prison, he looks back at the time with despair, saying, "Prison takes your soul."

He continued: "The time that you're away from your family, your friends, your life, you never get it back. You never get it back."

Watch the video below or at this link.