Identify this choral piece?

Cafe Society
#1

About halfway through this inspirational video:

http://www.wimp.com/lifemarathon/

…the soundtrack breaks into a choral piece. It sounds familiar, very familiar, but I can’t put my finger on it. Gilbert & Sullivan, maybe?

Can anyone out there tell me what it is?

#2

Do You Hear the People Sing from Les Miserables.

#3

That’s the one they wrote right after HMS Pinafore, right?

But seriously, thank you!