When celebrated comedian and actor Robin Williams passed away on August 11, 2014, talk show host Conan O’Brien received the news during a taping of his late night show, Conan. He shared the sad story with his audience.

“We’re so very sorry that we have to report this,” O’Brien told the audience. “This is absolutely shocking and horrifying and so upsetting on every level. We’re absolutely stunned.”

In a way, O’Brien, Andy Richter and guest Will Arnett’s shock at the news is a tribute to Williams gravity in the entertainment industry and as a coveted guest on late night television.

Whenever Williams would make an appearance on the Late Show, Late Night, Conan or The Tonight Show, it was an occasion. You knew you were in for something unexpected.

Rather than try to collect the very best of Williams’ appearances, we thought a better testament would be to the breadth, depth and variety of appearances Williams has made. Here are some of our favorites:

1. Robin Williams first appearance on The Tonight Show
Williams makes his first appearance on The Tonight Show starring Johnny Carson in 1980 before the fourth season of ABC’s Mork & Mindy and prior to the release of The World According to Garp. Carson notes that Williams already appeared on The Dick Cavett Show. Williams displays his first moment of improv, too, standing up out of his seat to imitate Flipper.

2. Robin Williams last appearance on The Tonight Show
Williams joins Jay Leno prior to the debut of his return-to-television sit-com The Crazy Ones in summer 2013. In a bit of sad serendipity, Williams bookends his appearances with another joke about dyslexia.

He debuted on Carson with a joke about dyslexia. “On Halloween, I went trick-or-trout.”

3. Robin Williams on The Talk
Promoting his CBS show, Williams appeared on The Talk. In a very touching moment, talk show host Sharon Osbourne shares a story in which her husband, rocker Ozzy Osbourne, reached out to Williams - who neither personally knew - to ask the actor if he would spend five minutes with Osbourne, who was physically ill and not doing well. Osbourne was a fan and her husband hoped the humor would make her feel better. Williams stayed for more than hour, getting in bed with the Osbourne and making her laugh.

4. Robin Williams on the Late Show with David Letterman
Williams has made numerous appearances on Letterman’s two talk shows. In this clip, from 2011, Williams discusses his return to Broadway. Also, in typical Williams fashion, he rouses the audience by leaping out of his seat when discussing the Academy Awards.

5.Robin Williams on The Graham Norton Show
Did you think Williams iconic guest appearances were relegated to U.S. television? Not so. Here he appears on the BBC’s The Graham Norton Show. Here he recycles a few jokes about winning the Academy Award for Good Will Hunting and imitates his mother after he forgets to thank her during his Oscar acceptance speech.

6. Robin Williams on the Late Late Show with Craig Ferguson
Maybe one of my favorites. Here Williams and late night host Craig Ferguson discuss there shared concerns over offending people with their comedy. After Ferguson says the only people you don’t have to worry about offending are Nazis, Williams shares a story, which he contends is “very true,” about appearing on a German talk show. When the host asked him why Germany is always perceived as not having any humor, Williams says he responded, “Did you ever think that it’s maybe because you tried to kill all the funny people?”

7. Robin Williams on The View
Worth watching if only to see Williams reunited with his Comic Relief counterpart and good friend Whoopi Goldberg.

8. Robin Williams on Jimmy Kimmel Live
Again promoting his return to primetime teleivision in The Crazy Ones, WIlliams appears on Kimmel to thunderous applause. It only takes 30 seconds for Williams to stand-up and place his leg seductively on Kimmel’s desk, after the talk show host compliments him by saying that it is only when Williams is on the show that he feels like he’s actually hosting a talk show. Watch this clip and compare it to Williams more subdued appearance on Leno around the same time. Says something about the vibe of those late night programs.

9. Robin Williams on The Ellen DeGeneres Show
Too much fun. Here Williams and talk show host Ellen DeGeneres play “Heads Up,” in which Williams provides accents and impressions and Ellen must guess who he is portraying.

10. Robin Williams on Live with Kelly and Michael
Many of these clips are from Williams promoting The Crazy Ones, but they all illustrate the kind of energy Williams would bring to a talk show set. This one is no different.

11. Robin Williams on The Arsenio Hall Show
Williams shares stories from the set of Being Human on The Arsenio Hall Show - Arsenio’s first and most successful talk show. Williams shares a quick story about being the first choice for the Joker in Tim Burton’s Batman, but was turned down when Jack Nicholson became interested.

Do you have a favorite Robin Williams talk show clip? Share it with us by sending me a note at talkshows@aboutguide.com.