'Tis a sad day for comedy.

Late-night host Conan O'Brien ended his show last Monday on a very somber note.

During the taping of O'Brien's show, the comedian, along with co-host Andy Richter and guest, Will Arnett, found out about the death of Robin Williams, one of the world's comedic greats.

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At the show's closing, O'Brien broke the news to his audience, "This is unusual and upsetting, but we got some news during the show that Robin Williams has passed away," O'Brien shared.

The audience was flabbergasted as O'Brien apologized for relaying the news during their time of merriment. He said that the news isn't only shocking, it was horrifying and absolutely upsetting.

Richter followed suit and sent out a message to Williams' family, sharing that the actor was an amazing and extremely kind man.

With a shaky voice, Arnett shared his own thoughts regarding his former colleague and friend. The "Teenage Mutant Ninja Turtles Star" shared that Williams truly is one of the greats, but as much as he was wonderful onstage, he was an even better human being offstage.

"Just the loveliest, sweetest, one of the kindest guys that I've ever worked with ... just such a soft, warm, emotionally sweet guy, and it's a major, major loss for everybody," Arnett added.

As a final word, O'Brien ended by saying that everybody in the studio was still processing the news of the actor's untimely death and, that their thoughts were with Williams' family. "We're thinking about everybody he touched around the world throughout his life, we're thinking about Robin tonight," he said.

Robin Williams was 63 years old when he passed. Police authorities said that the cause of death was asphyxiation and, that the comedian had taken his own life.

Before his death, the actor was said to have been battling with depression.

TagsRobin Williams, death, Conan O' Brien, Andy Richter, Will Arnett, TV show, Video