Ken Jeong was not happy withThe Masked Singer’s choice to cast Rudy Giuliani as a contestant, a source close to the set tells PEOPLE.

During last week’s taping of the Fox series' season 7 premiere, former New York City mayorRudy Giulianiwas unmasked as one of the contestants,Deadlinefirst reported.

After Giuliani was revealed as the contestant, Jeong, 52, and fellow judgeRobin Thickebothwalked off the stage, according to the outlet. The other judges,Jenny McCarthyandNicole Scherzinger, reportedly remained on stage after the reveal, where they briefly chatted with Giuliani, who is also former PresidentDonald Trump’s former attorney.

“Ken was super upset and indeed stormed out,” the source says. “Robin actually followed him because he and Ken are very close friends and he wanted to check on him. Robin didn’t storm out because of Giuliani.”

“Ken felt disrespected and was livid to see Rudy was under the mask which is why he walked off. There’s no way he could hide his feelings,” says the insider.

The insider adds that Jeong — who earned his medical degree from the University of North Carolina at Chapel Hill and practiced medicine for several years in Los Angeles — has long expressed his political views, which are in direct opposition of Giuliani.

“Ken has been incredibly vocal about how the previous administration handled many things but especially COVID-19 and has found a lot of what they’ve said not only wrong but dangerous,” says the insider. “To get someone who helped to spread misinformation and call into question the accuracy of our election and democracy to appear on his show was going to set him off.”

Efforts to reach Giuliani were unsuccessful.

Araya Doheny/WireImage; Roy Rochlin/Getty

ken jeong rudy giuliani

Giuliani, 77, has been a controversial figure throughout his career in politics, but has faced particular scrutiny since his time serving as the personal attorney for Trump.

Rudy Giuliani.SAUL LOEB/AFP via Getty

Rudy Giuliani

His erratic behavior in recent years has also raised eyebrows, including the viral video of himsweating profusely during a Trump press conference, his infamous appearance inBorat Subsequent Moviefilmas well as the time he was filmedshaving his facewhile seated in an airport restaurant.

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Giuliani is not the first politician to be a contestant onThe Masked Singer,which is set toreturn for its seventh seasonon Fox on March 9.

source: people.com