Michael Flynn, the disgraced former national security adviser, campaigned for a Republican congressional candidate in California on Friday, making it his first public appearance since pleading guilty to lying to the FBI last December.

The Daily Beast reported Flynn was coming "out of hiding" to endorse Republican Omar Navarro in his challenge against U.S. Rep. Maxine Waters, the 14-term Democrat in California’s 43rd Congressional District.

Flynn reportedly attended a public event in La Quinta, Calif., about 130 miles east of Los Angeles. Navarro lost to Waters by more than 50 percentage points in 2016 in the strongly Democratic district.

Navarro said he and Flynn had been corresponding since meeting at last month’s Conservative Political Action Conference (CPAC) in Maryland, the Washington Examiner reported.

At the Friday event, Navarro slammed Waters, called for the president to endorse him and repeated an insult from Trump that Waters has a “low IQ.”

Waters hit back at Navarro and Flynn in a series of tweets, including noting that Navarro was on probation for a criminal conviction of installing a tracking device to his wife’s car.

Flynn’s appearance was the latest sign that he is re-entering political life while still awaiting sentencing and cooperating with Special Counsel Robert Mueller’s investigation into Russian election interference and possible collusion with the Trump campaign.

Mueller is also investigating the president’s possible obstruction of justice. As it relates to Flynn, the special counsel’s prosecutors have signaled intentions to interview Trump about his firing of Flynn, his conversations with former FBI Director James Comey and the FBI’s investigation into Flynn.

In February 2017, Flynn resigned under pressure from his role as national security adviser after it was revealed he misled Vice President Mike Pence about his contacts with Russian officials.

The retired Army lieutenant general frequently campaigned for Trump in the 2016 presidential campaign, leading the Republican National Convention crowd in anti-Hillary Clinton “Lock her up!” chants.

“If I’m paying the price for that decision [to join the Trump campaign], so be it and God can and will judge me at some point,” Flynn said to the crowd Friday.

The Associated Press contributed to this report.