“The big question remains, will Robert Mueller testify?” Stephen Colbert asked in his Late Show monologue Tuesday night before answering his own question with a big shrug.

In the aftermath of the Mueller Report, the special counsel has expressed his willingness to testify before Congress, but President Trump has made it clear that he does not want that to happen and now Attorney General William Barr has said he has “no objection” to Mueller telling his side of the story under oath.

“And that’s important,” Colbert said, pointing out that as the head of the Justice Department, Barr is technically Mueller’s boss and could block him from testifying if he wanted to. “Just like how, as a CBS employee, my bosses can prevent me from going on Naked and Afraid,” the host joked. “Even though I am both of those things at least twice a day.”

“No wonder Trump wants everyone to drop this Mueller stuff,” Colbert added. “Most people, it turns out, don’t believe that he was ‘totally and completely exonerated.’”

According to a recent NBC/Wall Street Journal poll, just 50 percent of Fox News viewers believe the Mueller Report cleared Trump of all wrongdoing, as he has repeatedly claimed. (That number is significantly smaller for those who get their news from any other major media outlet.)

“They don’t know whether to believe the president,” Colbert said. “That’s an existential crisis for Fox viewers.”

“And that deep uncertainty has started showing up in ads, like, ‘I’m not even sure if this is MyPillow,’” he joked, citing one of Tucker Carlson’s few remaining advertisers.