In the world of theater, long-running and successful shows like “The Phantom of the Opera” or  “Cats” hold a special place in the hearts of theater-lovers worldwide. Now, Boston’s very own “Shear Madness,” a comedic whodunnit that takes place in a hair salon, is celebrating its 40th anniversary at the historic Charles Playhouse where it debuted.  

“Shear Madness” has been translated in 10 different languages and spawned 42 productions in the U.S. according to Broadway In Boston. Marilyn Abrams, one of the show’s creators alongside Bruce Jordan, said she prides herself on the originality and “magic” behind each night’s show.  

 “The audience finds themselves a part of it without thinking that they’re ever going to be a part of it,” Abrams said. “Being in the play is actually why Bruce and I took it and stayed with it for so long and worked so hard to get it going, because we were in it.”

Jordan said he thinks the show has maintained its strength due to its ability to keep itself “eternally fresh and new.” As an interactive, improvisation-based performance, no two shows are ever the same.

“The jokes that are today, were not the same jokes that were a month ago,” Jordan said. “[Audiences] see different things each time that they come.”

Along with producing and directing the show respectively, Abrams and Jordan also held roles in the production’s early days. Abrams said that her time as an actress in the show created a unique connection that she had never experienced with previous roles. 

“I have to say that being in the show, in Boston, in that little theater and working with the original cast, to me personally is so meaningful,” Abrams said. “And the people who were the founding fathers, who were in the show with us 40 years later, it’s just as real as it was. I feel so much love and affection for my fellow actors in the play.”

With the show’s innovative structure comes unique audience experiences that can’t be found in the traditional theater environment. Abrams’ stand out moment with an audience member over the show’s 40-year run came in the form of a misplaced coat. 

An audience member accidentally mistook a prop coat hook for a real coat hook and hung his designer Burberry coat upon it. Little did he know, a cast member — who had to wear a Burberry coat for the show — incorporated that same coat hook later in the performance. 

Jordan also recounted the time a casual, improvised conversation with an audience member took an interesting turn. 

On one particular night, Jordan’s character was cooking, and the audience member wanted to know if he had the correct ingredients. Jordan, following the show’s comedic nature, purposefully kept messing up the order of the ingredients. 

“I’m writing it down and each time I write it down, I write it down a little wrong and repeat it back to him,” Jordan said. “And he gets out from behind his chair, just goes up the stairs into my kitchen (the set). Fortunately, the police officers stopped him. But I thought now that’s the magic of theater.”