Broadway is buzzing over a $6.3 million lawsuit filed by top theater ad agency SpotCo against top producer Scott Rudin.

SpotCo alleges Rudin hasn’t paid his bills. Sources told us Rudin’s now prepping a countersuit as soon as this week.

An insider huffed, “These are typical grievances between a producer and a vendor,” and added Broadway is hurting since shows shuttered. But SpotCo said its complaint predates the pandemic.

A lawyer for Rudin’s company said they’ll “vigorously” fight the case.