EDITOR’S NOTE: The Glass Bottom Boat was one of the first movies on the CBS Late Movie, airing on February 17, 1972. It also aired on July 31, 1972; February 19 and November 5, 1973 and March 12, 1976.

Also known as The Spy in Lace Panties, a title change that was likely made to emphasize the spy plot, this movie teams up animator-turned-director Frank Tashlin (who made one of my favorite movies of all time, The Girl Can’t Help It) and star Doris Day, who gets to sing, of course, but also gets pulled into a spy plot. It was written by Everett Freeman, the writer of The Maltese Bippy.

Day plays Jennifer Nelson, a widow helping her father (Arthur Godfrey) in his tourism business by dressing as a mermaid and swimming under his glass bottom boats. One day, she’s accidentally caught by Bruce Templeton (Rod Taylor) while he’s fishing; the embarrassment of her being nearly nude in front of him is compounded when she realizes that he works at her new position of employment, an aerospace research company.

Bruce’s new project is GISMO, a gravity system, and he hires Jennifer to write his biography. But really, in truth, he just wants to get with her. Jennifer also meets Julius Pritter (Dom DeLuise), a spy struggling to install a stereo in Bruce’s futuristic apartment while gathering information on him, and Edgar Hill (Eric Fleming), a CIA agent protecting Bruce and GISMO.

Love blooms, as it does in romantic comedies, but the issue is that Hill, security guard Homer Cripps (Paul Lynde!) and PR executive Zack Molloy (Dick Martin!) believe that Jennifer is a spy. Why would she call the same phone number multiple times a day and simply hang up after saying, “That’s enough, Vlamdir?”

As it turns out, ‘Vlamdir’ is not a Russian boss, but Jennifer’s dog. The poor pup’s only exercise during her work hours is running around the apartment, irritated by the ringing phone. In a classic rom-com twist, Bruce makes a blunder by underestimating Jennifer’s intelligence. She decides to play along and pretends to be a spy. This leads to a series of light-hearted hijinks at a party, but all’s well that ends well.

For TV aficionados, Norman and Mabel Fenimore (George Tobias and Alice Pearce) are the same characters Tobias and Pearce played on Bewitched. The film also features a memorable cameo by Robert Vaughn, and the theme from The Man from U.N.C.L.E. is heard on the soundtrack. Speaking of the show, Templeton’s ultra-technological apartment was repurposed as the evil spy base on a two-part episode of The Man from U.N.C.L.E., titled ‘The Concrete Overcoat Affair.‘

After this, Day only made four more movies — including the pure spy movie Caprice with Tashlin  before starting what many would know her best for: The Doris Day Show. In that show, she sang the theme song, “Que Sera Sera,” which became synonymous with Day’s career and was also featured in her earlier films, like The Man Who Knew Too Much and Please Don’t Eat the Daisies.