According to Teddy Reno, the whole take of the letter (perhaps the most famous and referenced of the entire movie) was totally ad-libbed by both Totò and Peppino De Filippo. They were often unsatisfied with the script of the movie and frequently diverted from it: the letter take was one of the most successful.
The film was a huge box office success in Italy but was poorly received by critics, who called it "a spectacle of the worst quality" in spite of "the presence of two good actors like Totò and Peppino De Filippo" (L'Avanti). In modern days, the film is generally regarded as a classic Italian comedy.
Teddy Reno stated that while filming the scene of the letter, a light operator bursted out laughing: the scene had to be reshooted, with the producers being so angry with the operator that he was fired. The cast persuaded then to the company to call him back, despite being annoyed to have to reshoot a scene which was nearly perfect. The scene was remade a couple of days later because Totò and Peppino De Filippo needed some time to take inspiration back. Most probably the scene edited into the movie includes part of the original shooting.
The famous scene with the two uncles writing the letter addressed to their nephew's "seductress", which was mostly improvised, has been referenced many times in Italian comedies, including in Non ci resta che piangere (1984), Ho visto le stelle (2003) and Maschi contro femmine (2010) and the TV cabaret show Zelig.
The villa where Gianni (Teddy Reno) and Marisa (Dorian Gray) are on holiday is at 33 Via Posillipo in Naples. The same villa is used in the TV-series Un Posto Al Sole as the exterior of Palazzo Palladini. Palazzo Donn'Anna can be seen in the background.