
What a great clip - Irene is one of those old gems that feature Lindy Hop in its heyday (misidentified in the clip as "Jitterbug").
Hattie in the front of the dance line towards the end does the "Shorty George" - named after Lindy Hop pioneer Shorty George Snowden, a short guy who took advantage of his height by dancing with large women. I wouldn't be surprised if that's another one of Harlem's famous troupes on stage with Hattie, Whitey's Lindy Hoppers. They appeared in a handful of movie dance sequences in the '30s most notably Hellzapoppin (1938) where they popularized aerials in swing dancing and brought their style to the mainstream. I'm gonna have to do some research now and get back to you. A lot of Lindy Hop websites don't list Irene.