"My friend. RIPJoanRivers," comedian Margaret Cho tweeted as soon as she learned Joan Rivers' death.

Considering herself the 81-year-old veteran comedienne's protégé, Cho tweeted, "like u, i was an ugly duckling. then you taught me to become a swan. and we'd laugh, because finally, we were swans together. #RIPJoanRivers."

"There is so much to say, but my grief stuns me into silence, so for now, let me just say THANK YOU #RIPJoanRivers," the South Korean-American comedienne also tweeted.

On April 6, 2013, Cho appeared on Rivers' weekly internet talk show "In Bed With Joan." In this sixth episode of the show, the two comediennes talked about dating Quentin Tarantino and Cho showed off her tattoos.

In August, Cho also paid tribute to the late comedian Robin Williams, who she said was the first celebrity she ever met.  

Cho grew in San Francisco, which has a special connection with Williams, according to Time.  

"When I started comedy in San Francisco in the '80s, Robin would hang around the clubs I started doing shows at and grew up next to. He would always come in, and then later, of course, we would always see him in clubs here," Cho recalled.

For Cho, Williams "was the patriarch of our little clan of comedians in San Francisco. All of us looked at him, in a way, as a father figure. That's why this is so upsetting."

Along with Will Durst and Marga Gomez, Cho will be among the headliners of San Francisco's Comedy Day on Sept. 14 at Sharon Meadow in Golden Gate Park, ABC7 News reported.

At the five-and-a-half hour comedy festival, organizers will show a special tribute to Williams who performed in the very first San Francisco's Comedy Day 34 years ago and continued appearing in the annual event over the years.

Meanwhile, Fox passed on the pilot comedy titled "Cabot College" executive produced by "30 Rock" star Tina Fey starring Cho, Fortune Feimster and Bonnie Dennison, according to Hollywood Reporter.