WATCH: Jimmy Fallon Thanks David Letterman in Emotional Tribute

Well this isn’t something we’re used to. Jimmy Fallon will leave you in tears as he bids farewell to David Letterman

On the eve of Letterman’s retirement, Fallon took a moment on Monday’s (May 18, 2015) The Tonight Show to pay tribute to the late night host, offering a few memories of what Letterman has meant to him over the years.

I want to take a minute to talk about David Letterman, who I’m sure everyone here knows will be retiring after 33 years of innovation, fun and just plain weirdness—but mostly fun. I, like many of you, grew up watching Dave. Everybody did. I mean, if you saw somebody throw watermelons off a roof and you go, ‘Oh my gosh. Adults get paid for doing that?’ That type of stuff had never been done on TV before. This is at 12:30. This is after The Tonight Show. All you had was Johnny Carson, so this is kind of like unexplored space. This is like the Wild, Wild West. I think this show and what late-night has become is a result of him playing with the genre and experimenting and exploring and doing that stuff. I, like every kid who grew up watching him, will miss him.

Fallon then shared a more serious memory with viewers, becoming particularly emotional as he remembered Letterman’s reaction following 9/11.

He’s always just there when you need him. I remember after 9/11, we needed somebody. The city was in shock. We’re all looking for answers. We wanted to see what Dave had to say and we looked at him to say something. He said, ‘There is only one requirement for any of us and that is to be courageous, because courage, as you know, defines all other human behavior.’ We needed that. David Letterman is courageous.

Have a nice retirement, Dave.

Letterman’s final Late Show airs tonight (May 19, 2015) on CBS.