Stewart broke the news at the end of Monday's broadcast.
"I will be wearing a suit. I will more than likely be showered," he said. "I'm hoping that you will join us for that program."
Stewart, who took over as host in 1999, announced in February that he would be stepping down sometime this year.
His is the latest high-profile retirement in the world of late night, following the departures of Jay Leno and Craig Ferguson last year. David Letterman will also step down later this year, to be succeeded by Stewart's friend and former Comedy Central colleague Stephen Colbert.
The August departure date means that Stewart's replacement, South African comedian Trevor Noah, will take over before the 2016 presidential campaign is in full swing.
Noah, a surprise pick for the job, has come under scrutiny for tweets that some considered anti-Semitic and sexist, but Stewart defended his replacement earlier this month.
"Trevor Noah will earn your trust and respect ... or not. Just as I earned your trust and respect ... or did not," he said.
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