Fats Waller Library of Congress Prints and Photographs Division/New York World-Telegram and the Sun Newspaper Photograph Collection/Alan Fisher

If you’re not among the ticketholders for tonight’s sold-out performance of “Chicago’ at The Rep, The Weekend Theater’s next show is open just down the road, with Director Danette Scott Perry, Music Director Jonathan Doram and a host of vocal talent — Antwon J. Staton, Christopher Watkins, Jaelynn Epps, Rosa Howard and Valarie Foster — paying homage to Harlem stride style innovator and rock harbinger Fats Waller with “Ain’t Misbehavin: The Fats Waller Musical Show.”

Pregame with this performance clip of “Ain’t Misbehavin’” from the 1943 musical “Stormy Weather,” proof positive of Fats Waller’s mind-boggling boogie piano technique, his easy way with a crowd and his nimble shapeshifting, taking the play’s supple title tune from ballad to romp to shoulder-shimmy cabaret.