Joan Rivers Honored by David Letterman and Conan O’Brien in Emotional Tributes

AP Images/Invision

Note: We'll update this post as more tributes come in.

Joan Rivers is getting a proper sendoff from TV's late show hosts. The comedian died at 81 Thursday.

David Letterman called Rivers a comedy "pioneer" on Thursday's The Late Show.

“Here’s a woman, a real pioneer for other women looking for careers in stand-up comedy,” said Letterman. “And talk about guts – she would come out here and sit in this chair and say some things that were unbelievable, just where you would have to swallow pretty hard… but it was hilarious… the force of her comedy was overpowering.”

Conan O'Brien recalled watching Rivers when she would guest host on Johnny Carson's The Tonight Show.

"When she did, it was an event. Everybody in the country would talk about it the next day," O'Brien said on TBS' Conan! "People would gather in the living room. Everyone would howl with laughter. ... At that time she was so outrageous and her comedy -- it felt so out of the bounds and people were just blown away."

Rivers broke the late night glass ceiling as a permanent guest host for The Tonight Show and then with her own late-night show on Fox. The latter caused a rift between her and Carson, with Rivers recounting in a 2012 essay for The Hollywood Reporter how he never spoke to her again. She was effectively banned from The Tonight Show, until she returned earlier this year to Fallon's incarnation.