Fallon invited Rivers back to The Tonight Show after more than 25 years — Johnny Carson famously blacklisted her from the show that made her a star after she left her gig as his permanent guest host for her own late-night show on Fox in 1986.
And when Fallon looked back on his first episode of The Tonight Show, which marked one of two times she returned to the show under his helm, he got a bit choked up (or verklempt, as Rivers would probably have said).
The longtime Late Show host talked about the guts Rivers had to say some "unbelievable" things on his show, her pioneering efforts as a female comedian, and her work ethic, noting she did about 300 shows a year.
The former host of The Tonight Show remembered watching Rivers when she would sub in for Johnny Carson, talking about what an event it was to watch her guest host. "Everybody in the country would talk about it the next day," he said.
The Late Night host mourned Rivers, looking back on when he had the opportunity to interview her on his show. "I have not sat next to anyone who told more jokes faster than Joan Rivers did when she was here," he said.
The Late, Late Show host called it "a sad day for us in the comedy community," before cracking a joke about her red carpet commentary.
The ABC late-night host noted he "had the good fortune of having Joan on the show like six times," before he showed a clip of her most recent guest stint. "She was so funny," he said. "Keep in mind, in this clip, this woman is 80 years old in this."
The Daily Show host ended his show on Thursday honoring Rivers by making a bit of hers his "Moment of Zen."