‘Witness for the Prosecution’ to screen in Sonoma on Feb. 13

“The management of this theater suggests that for the greater entertainment of your friends who have not yet seen the picture, you will not divulge, to anyone, the secret ending of ‘Witness of the Prosecution.’”

That stern disclaimer, made by an anonymous, lawyerly-sounding voice, was originally played in theaters over the end credits of Billy Wilder’s Oscar-nominated 1957 adaptation of Agatha Christie’s twisty courtroom thriller. Presumably, Sonoma audiences will get to hear it at the conclusion of the film’s Vintage Film Series screening at the Sebastiani Theater, Monday, Feb. 13.

Featuring the final screen performance of matinee idol Tyrone Power – who died of a heart attack before completing his next film, “Solomon and Sheba” – “Witness for the Prosecution” was marketed on the strength of its “surprise ending.” Even the movie’s posters, exuberantly claiming, “The most electrifying entertainment of our time!” also contained the tantalizing warning, “You’ll talk about it – but please don’t tell the ending.”

The film takes place largely within London’s Old Bailey courthouse, where an accused murderer (Power) is being defended by the legendary but ailing Sir Wilfrid (Charles Laughton), at the objection of his private nurse (Elsa Lanchester, who was married to Laughton). Marlene Dietrich plays Power’s wife, the “witness” of the title, giving one of the best performances of her career, and contributing significantly to the big ending the filmmakers fought so hard to keep secret. All of this mystery – which included the actors themselves not receiving the final script pages until the end of the shoot – clearly had the desired effect. The film was a hit, tripling its $3 million dollar budget and earning Oscar nominations for six Oscars, including Best Picture and Best Director, with acting nominations going to Laughton and Lanchester – but not Dietrich, whose performance was not championed by the movie studio, because any full discussion of what she so expertly accomplishes contained unfortunate “spoilers.”

It’s clearly a secret worth keeping.

The American Film Institute has named “Witness for the Prosecution” the 10th best courtroom drama ever made, after “A Few Good Men,” “The Verdict,” “Kramer vs. Kramer,” “12 Angry Men” and “To Kill a Mockingbird.”

Email David at david.templeton@sonomanews.com.