Frank DiLella delves into the world of the new Broadway play “The Lifespan of a Fact,” based on the real life story of writer John D’Agata and Jim Fingal, the fact checker who caught inconsistencies in an essay John wrote for a magazine. Daniel Radcliffe and Bobby Cannavale talk about playing the two writers, and D’Agata and Fingal weigh in with what really happened.

"On Stage" is New York City's premier theater show, seen Saturdays and Sundays at 7:30 p.m. and 10:30 p.m.