The loss of Joan Rivers not only shocked and saddened the masses; it also hit the world of comedy hard. And it seems fellow comedian Jerry Seinfeld is sharing some thoughts on the late television star, who he reveals was set to be a guest on his web series "Comedians in Cars Getting Coffee."

In a post on Facebook, Seinfeld declared his admiration for Rivers.

"I just came across this heartbreaking text on my phone from August 19th," wrote Seinfeld on the Facebook page of his web series. "I had asked Joan Rivers to be our lead guest on the new season of Comedians in Cars, and she was thrilled. Then we got a call saying she was going in for a medical procedure and needed to postpone."

Jerry Seinfeld also shared a photo of the text message, which appears to have been sent on Aug. 19, just a few short weeks before Rivers' death on Sept. 4.

Joan Rivers passed away after going into cardiac arrest while undergoing an endoscopic procedure in New York City.

"I would have loved to have shown another side of her," added Seinfeld in his Facebook message. "I wanted to tell her how much I admire all she had accomplished, especially in the latter stages of her career. She was one of the greats. I'll miss her."

"Comedians in Cars Getting Coffee" is a web series that airs Thursdays at 12 pm EST.

In the show, which is supported by the network Crackle, Jerry Seinfeld picks up a guest comedian in a vintage car and takes him/her out for coffee or to a restaurant.

Past guests have included David Letterman, Jay Leno, Larry David, Alec Baldwin, Louis C.K., Chris Rock, Howard Stern, Tina Fey and Sarah Silverman.