The comedian has already made his return to late night.
Just months after retiring as host of The Daily Show, Jon Stewart has already returned to late night twice in one week.
On Thursday's Late Show, the 53-year-old comedian reunited with his former Comedy Central cohort, Stephen Colbert, to bring attention to the Zadroga Act - a bill that funds health care for 9/11 first responders and is set to expire at the end of the year.
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Stewart interrupted Colbert's opening monologue to deliver his message, but barely completed a sentence before the Late Show host declared, "BORING!"
"I hate to go pro on you here, but you’ve been out of the game for a while. That’s got no zazz!" Colbert critiqued. "No one’s going to listen to you unless you Trump it up a bit. The media won’t pay attention to anything at all, unless you are Donald Trump."
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Colbert then placed a Trump-esque wig on Stewart and used a bag of Cheetos as "makeup" on his friend.
After a little encouragement, Stewart went full Trump, insisting that viewers tweet their congressmen with the hashtag #WorstResponders.
"Don't let Congress play politics with this necessary bill," Stewart said. "Donald Trump said pull up your big boy pants."
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On Monday, Stewart returned to The Daily Show to also speak on behalf of 9/11 first responders.
“I can't believe it! This is awesome!” current Daily Show host, Trevor Noah, said upon seeing Stewart. “Oh, wait, wait, wait, sh**. Are you here to take the show back? I heard about this in American TV.”
Of course, Stewart was only there for a visit. In fact, he told ET that he should have retired 10 years ago. "I had no idea that people were out having fun," he quipped.
As for Noah, Stewart seems pretty pleased with his predecessor. "Nobody should be that good," he contended. "He's four years younger now than I was when I first started the show and his just... his ease, and his grace, and confidence is just phenomenal. He's a phenomenal guy."
Check out ET's entire interview with Stewart: