I'd always wanted to check out this well-regarded if rarely-seen comedy for the record, some years back I missed out on its sole Italian TV screening (that I know of). For Tony Curtis, it meant something of a follow-up to the classic SOME LIKE IT HOT (1959) where he's forced, with his co-star (in this case, Dean Martin), to pass himself off as something he isn't (an F.B.I. agent), leading to misunderstanding, various complications and imminent danger.
Similarly, a female is involved in the shenanigans (Curtis' on and off-screen wife Janet Leigh) though, here, the whole ruse starts off because of her: Chemistry Professor Curtis' fling with a female student is discovered by his jealous wife, so he turns for help to his best pal TV writer Martin who procures him with papers (and a gun) denoting his Bureau affiliations; Leigh is finally convinced of this and, soon after, is contacted by a real F.B.I. operative (James Whitmore) who uses her to keep track of just what Curtis and Martin are up to!
One of the highlights of the film is the extended yet splendid incident in a restaurant: Leigh accepts Curtis' excuse to go on the town with Martin, believing it to be another federal job but, in her over-eagerness to help, effectively blows his cover
which then lands the F.B.I. itself in hot water! The biggest trouble, however, is that enemy agents take the two men to be the real deal and kidnap them (and Leigh) in order to extract vital information they believe Curtis is in possession of! The aftermath of this sequence is again hilarious as, dazed by the drug he's been given, Curtis thinks they've been taken to a Russian sub and persuades Martin to flood it
but it transpires that they're in the basement of the Empire State Building!
The script (adapted by Norman Krasna who also produced from his own play) balances witty dialogue with inspired zany situations, which are then delightfully put across by an excellent cast. Both male stars, in fact, were already adept at this type of thing (crooner Martin also sings the title tune), but Leigh surprisingly proves a fine comedienne in her own right: it's a pity that her marriage to Curtis was crumbling by this time which is doubly ironic given the film's plot, but they were professional enough not to let the real cracks show in their performances.