Do I have to give a spoiler alert about a film that came out in 1957?

“I never should have gone panty-less in that mini skirt!”

Because “Your Past Is Showing” (also known as “The Naked Truth”) ends with a sequence in which Nigel Dennis, a scandal-mag reporter, taken hostage and flummoxed from repeated head wounds inflicted by some of the semi-prominent people he’s tried to blackmail, tries to step out for some fresh air, not realizing he’s on a zeppelin. Then, Peter Sellers’ character fires a celebratory shot from a pistol in glee at Dennis’ death, piercing the vessel and sending it — and my thoughts on the movie’s humor — spiraling into the ocean like a child’s balloon.

Almost always the worst idea to have in any situation. Unless you are “MythBusters.”

Too bad, because there’s so much to like about this film, particularly the performance of the stately Peggy Mount as plagiaristic author Flora Ranson, who we meet when she is swinging out of a window to leap to her death. But wait! She’s coming back inside — to finish her tea. And when her boisterous jump kills nothing but a shop’s awning beneath her, she brushes the very public experience off with the clever nobility of a house cat who has just tumbled off a window ledge in sleep. Ransom doesn’t just pinch plots from other authors — she arguably steals the show from Peter Sellers in this production.

“Your Past Is Showing” very nearly succeeds at being one of those successful, silly summer movies people refer to as a “frolic,” where the actors are clearly having great fun and the happy audience forgets what they watched a few seconds after leaving the theater. But after a string of amusing set-ups — one blackmail victim’s humorous failure when she tries to gas herself in an oven, her head on a pillow, another victim’s too-polite attempt to purchase “a Mickey Finn,” and another victim falling in a river, then a lake, when ruses meant for Dennis ensnare him instead — the production turns as cheesily frenetic as an “Animaniacs” episode (probably No. 104, “Hercule Yakko,” with the “finger Prince” joke.)

“Jersey Shore,” the really, really, really, REALLY early years.

While this study of gossip, desperation and conspiracy does an overall decent job in making punchlines out of suicide and murder, the last half hour contains so much ham it needs its own sugar glaze. In the hands of writer Michael Pertwee and director Mario Zampi, Peter Sellers’ formidable wit is inexplicably muted in the character of Sonny MacGregor, the TV personality with a million personalities. When MacGregor learns his secret income from being a slumlord is about to be made public, he decides to kill Dennis by planting a bomb — which he clearly has to go to Ireland to get. Was that a laugh line in the theaters? Because it’s so lazy.

We’re lucky, though. Seven years after “Your Past Is Showing” came out, Sellers would be lucky enough to redeem bomb jokes for all time — as the star in “Dr. Strangelove.”

Ashley O’Dell reviews movies that aren’t in the theater anymore and has been providing trenchant critiques on turkey guillotines on Twitter since 2007. She lives in North Hollywood, near the In-N-Out Burger.