Writing for Slash Film, Jeremy Smith explores the complex casting process for Some Like It Hot, noting that Jack Lemmon didn’t get the part of Jerry until Marilyn signed on. United Artists wanted Frank Sinatra to play Joe, and Anthony Perkins was briefly tipped as Jerry.
But director Billy Wilder wanted Tony Curtis and Jack Lemmon – who had just won an Oscar for Mister Roberts, but was under contract to Columbia and wasn’t considered leading man material. After the success of Some Like It Hot, though, Wilder would work with Lemmon again on several occasions, most notably in his next film, The Apartment.
What isn’t mentioned in the article, however, is that Marilyn didn’t want to work with Tony Curtis, and had hoped that Frank Sinatra would play Joe – but she liked the script so much that she finally agreed. (This adds further context to Curtis’s infamous remark that kissing Marilyn was ‘like kissing Hitler.’ Still, it’s hard to imagine Ol’ Blue Eyes in drag …)
“Working in Wilder’s favour was his working relationship with Marilyn Monroe. He’d directed her in 1955’s sublime The Seven Year Itch, and she was keen to collaborate with him again. This was bad news for Mitzi Gaynor, who was up for the part of crooner/ukelele player Sugar Kane. UA knew of Monroe’s interest during Wilder’s pursuit of Sinatra, and, though this would’ve blasted the budget skyward (Monroe was seeking 10 percent of the gross, which meant Sinatra would’ve probably wanted 15 or a ton of money upfront), the studio was more than happy to foot the bill. Stars didn’t come any bigger in 1959 than Sinatra and Monroe.
Once Sinatra stepped out of the picture, the signing of Monroe was crucial. UA made her deal, and was satisfied enough with her presence that they okayed the casting of Lemmon as Jerry (though Danny Kaye was also considered for the part). Curtis and Lemmon were perfectly paired (it’s incredibly difficult to imagine Sinatra making Wilder and I.A.L. Diamond’s dialogue sing), and Monroe couldn’t be more charming or hilarious as Sugar.”
The Marilyn Report 