This film, part of the Preston Sturges season at BFI Southbank, is on an extended run until February 17th at the cinema. Full details here.
Chicago Reader review:
Rudy Vallee turns in his best performance as a gentle, puny millionaire named Hackensacker in this brilliant, simultaneously tender and scalding 1942 screwball comedy by Preston Sturges—one of the real gems in Sturges's hyperproductive period at Paramount. Claudette Colbert, married to an ambitious but penniless architectural engineer (Joel McCrea), takes off for Florida and winds up being wooed by Hackensacker. When McCrea shows up she persuades him to pose as her brother. Also on hand are such indelible Sturges creations as the Weenie King (Robert Dudley), the madly destructive Ale and Quail Club, Hackensacker's acerbic sister (Mary Astor), and her European boyfriend of obscure national origins (Sig Arno). The Hackensacker character may be the closest thing to self-parody in the Sturges canon, but it's informed with such wry wisdom and humor that it transcends its personal nature (as well as its reference to such tycoons as the Rockefellers). With William Demarest, Jack Norton, Franklin Pangborn, and Jimmy Conlin.
Here (and above) is the trailer.