Many theatrical productions have dress rehearsals. Does a nude performance hold an “undress rehearsal”?
 
“Undress Rehearsal-Burlesque” was the title of a painting reported in a February 1937 newspaper. “In an idle moment we were wondering if a strip-teaser holds an undress rehearsal” was published in a May 1937 newspaper. “Do burlesque shows have undress rehearsals?” was published in a 1957 newspaper.
 
“Question of the Day: do adult film stars have undress rehearsals?” was posted on Twitter on June 8, 2009. “Do burlesque shows have undress rehearsals?” was posted on Twitter on March 10, 2014.
 
   
Wikipedia: Rehearsal
Dress rehearsal
The dress rehearsal is a full-scale rehearsal where the actors and/or musicians perform every detail of the performance. For a theatrical performance, cast members wear their costumes. The actors may use props and backdrops; they do not use scripts, although the stage manager and director might.
 
For a musical performance, the dress rehearsal does not require wearing formal concert outfits (e.g., tuxedos and gowns). In music, the dress rehearsal is the final rehearsal before the performance; while initial rehearsals will often involve working on challenging sections of the piece or pieces, during the dress rehearsal, the piece or pieces are typically played in their entirety.
   
14 February 1937, Philadelphia (PA) Inquirer. “Calm Beauty of Older Art Revealed at an Exhibition” by C. H. Bonte, pg. 12SO, col. 8:
One can readily enjoy “Act in No. 3 Ring,” “Time Off,” and “Circus Qualifiers,” while, in another field of presumed amusement, “Undress Rehearsal-Burlesque” seems to take advantage of the current strip-tease phase, in its areas of robust and none to lovely female flesh.
(Oil paintings of Dorothy Van Loan.—ed.)
 
13 May 1937, The World-Herald (Omaha, NE), pg. 14, col. 2:
In an idle moment we were wondering if a strip-teaser holds an undress rehearsal.         
 
18 November 1957, Richmond (VA) Times-Dispatch, “Show Time” by Earl Wilson, pg. 30, col. 3:
TODAY’S BEST LAUGH: Noel Coward’s new show is “Nude With Violin,” and some wondered if they had an undress rehearsal.
 
11 December 1957, Philadelphia (PA) Inquirer, Herb Stein “Hollywood” column, pg. 37, col. 7:
Do burlesque shows have undress rehearsals? (Connolly)
 
26 October 1958, Chicago (IL) Sunday Tribune, “Radio TV Gag Bag” culled by Larry Wolters, Magazine sec., pg. 35, col. 1:
ROBERT Q. LEWIS reports something new in show business: A burlesque house that puts on an undress rehearsal.
   
Google Books
Thespis:
A Gilbert and Sullivan enigma
BY Terence Rees
London, UK: Dillon’s University Bookshop
1964
Pg. 99:
‘The New Burlesque — An Undress Rehearsal.’ This illustration first appeared in the Christmas number of The Graphic, 1871, with this caption. It was reprinted by John Hollingshead in Gaiety Chronicles with the title ‘Rehearsal of Thespis’.
 
Twitter
John Martz‏
@johnmartz
Question of the Day: do adult film stars have undress rehearsals?
6:48 PM - 8 Jun 2009
   
Twitter
Steve Young‏
@bluejayrock
Random Sunday Thought: If plays and musicals have dress rehearsals, shouldn’t burlesque shows have undress rehearsals?
2:55 PM - 10 Apr 2011
 
Twitter
cowardice engine‏
@PontiusPyrite
Do pornos still have dress rehearsals or do they call them undress rehearsals
2:02 AM - 3 Jun 2013
 
Twitter
Security Humor, or most likely, not.‏
@SecurityHumor
Do adult entertainers (aka strippers) have undress rehearsals?
6:58 PM - 2 Nov 2013
 
Twitter
Mark O’Brien‏
@obrienmark
Do burlesque shows have undress rehearsals?
6:42 PM - 10 Mar 2014
       
Twitter
joshua groeneveld‏
@effyeahjosh
Do strippers have undress rehearsals?
7:06 AM - 8 Mar 2015
 
Reddit—Shower Thoughts
Do porn shoots have dress rehearsals?
submitted April 8, 2015 by kisu_senpai
COMMENTS
Lord_Jello_III
wouldn’t they more aptly be called “undress rehearsals”?
 
Twitter
King Of Queens‏
@MrMet41
@MaryCalviTV Are you sure that the nude play in the park are doing dress rehearsals, or maybe undress rehearsals ?
11:40 AM - 24 Aug 2016
 
Twitter
norma spencer‏
@norma__lll
are auditions for porn called undress rehearsals
2:43 PM - 13 Dec 2017
 
Twitter
Bob Swanston‏
@SwanstonRobert
#1pun A nudist play is coming to a West End theatre.
Undress rehearsals start next week.
7:00 AM - 18 Jan 2018