Norm MacDonald Tweets Amazing Robin Williams Story About His First Encounter With 'The Funniest Man In The World'

Celebrities from Sarah Michelle Gellar to Questlove have taken to social media to publicly mourn and celebrate the life of Robin Williams.

Norm Macdonald, too, took to Twitter this afternoon to share a personal anecdote about a funny, private moment he shared with Williams before the younger comedian's first appearance on "Letterman."

It's a must-read.

It was my first stand-up appearance on Letterman and I had to follow the funniest man in the world. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

I was a punk kid from rural Ontario and I was in my dressing room, terrified. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

I was on the phone to a friend back home when the funniest man in the world ambled by. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

There was no one else on the floor. In shock, I told my friend who just walked by. Only the funniest man in the world. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

He was a jewish tailor, taking my measurements. He went down on his knees, asked which way I dressed. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

I told my friend on the phone that the funniest man in the world was on his knees before me, measuring my inseam. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

My friend didn't believe me so I said, "Could you talk to my friend, sir. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

The funniest man in the world took the phone and for ten minutes took my friend's chinese food order. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

I laughed and laughed and it was like I was in a dream because no one else was there. No one. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

The place was out of Moo Shoo Pork, and there was nothing he could do about it. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

He angrily hung up on my friend and I was about to thank him when he said I hadn't even tried the jacket on. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

Then the funniest man on earth dressed me, a complete stranger, and i remember he ended with a windsor knot. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

He spoke mostly yiddish, but when he finished he was happy with his job and turned me to a mirror to present myself to me.#RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

No one witnessed any of this. No one. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

The funniest man alive was in my dressing room a good half-hour and was far funnier than the set I had to do soon.#RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

When he left my dressing room, I felt alone. As alone as I ever remember feeling. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

Until today. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014

Unacceptable. #RIPRobinWilliams

- Norm Macdonald (@normmacdonald) August 12, 2014