show must go on, the - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The proceedings must continue, no matter what unfortunate event has occurred, as in The chairman died yesterday but the show must go on. This expression is a theatrical credo dating from the 1800s and was transferred to other situations in the first half of the 1900s.