In the show, which was first broadcast in November 2011, the late great actor and comedian was discussing his and Jackson's use of the same drug - in markedly different contexts.
Williams needed it for heart surgery, whereas Jackson ultimately overdosed on it.
"Propofol, which's nickname is Milk of Amnesia," Williams recalled.
"Michael Jackson was taking propofol to sleep, which is like doing chemotherapy because you're tired of shaving your head."
Cue raucous laughter in the studio - the kind Williams conjured on countless occasions before his tragic suicide in 2014.
However, the joke might not sit so well if made more recently.
One misjudged gag aside, it's common knowledge that Williams was a special man, and we were recently provided with further evidence, which we frankly didn't need.
It was reported in March that the late actor would demand that any company hiring him for an event or film should also hire a specified number of homeless people.
Williams, who was 63 when he passed away, took the opportunity to make a difference to the lives of people around him.
According to booking agent Brian Lord, Williams' rider (basically a set of demands that forms part of a performer's contract - think 'only brown M&Ms', to cite a classic example) was specific when it came to hiring homeless people.
Lord was apparently in negotiations with Williams for an event and, after seeing his requirements, he said: "When I got Robin Williams' rider, I was very surprised by what I found.
"He actually had a requirement that, for every single event or film he did, the company hiring him also had to hire a certain number of homeless people and put them to work."
Lord continued: "I never watched a Robin Williams movie the same way after that.
"I'm sure that on his own time and with his own money, he was working with these people in need, but he'd also decided to use his clout as an entertainer to make sure that production companies and event planners also learned the value of giving people a chance to work their way back."
The news was highlighted recently on a Reddit thread where one person wrote: "He was a great man, I wish there were more like him. RIP."
Another Reddit user, who claims to have worked with the actor, wrote: "I worked on a project with him (What Dreams May Come), and he got paid a ton.
"The other A-listers just clocked in and clocked out.
"He would hang around the set all day, for instance taking the security guard's mother on a personal tour of the sets.
"At the end, the wrap party got cancelled at the last minute, due to budget crisis.
"Then, suddenly it was back on.
"He attended and was the last one to leave, made sure to talk to every last person.
"Then I read in the National Enquirer that he himself had paid the $50K out of pocket for the party, 'on the condition of anonymity'."
He's sorely missed, that's for sure.