The Kit Kat Club at the Playhouse Theatre is a West End theatre in the City of Westminster, located in Northumberland Avenue, near Trafalgar Square, central London. The Theatre was built by F. H. Fowler and Hill with a seating capacity of 1,200. It was rebuilt in 1907 and still retains its original substage machinery. As of November 2021, the theatre has been refurbished and is home to a revival of the musical Cabaret with a seating capacity of 550.

Northumberland Avenue is a street in the City of Westminster, Central London, running from Trafalgar Square in the west to the Thames Embankment in the east. The road was built on the site of Northumberland House, the London home of the Percy family, the Dukes of Northumberland between 1874 and 1876, and on part of the parallel Northumberland Street.