In the "Ain't There Anyone Here for Love?" sequence, Jane Russell's fall into the pool was an accident. When Howard Hawks saw the dailies, he kept it in the film.
Marilyn Monroe reportedly suggested the line "I can be smart when it's important, but most men don't like it."
This was Jane Russell's only film with Marilyn Monroe. They got along well. According to Russell's 1985 autobiography, she called Monroe "Blondie" and was often the only person on the set who could coax Monroe out of her trailer to begin the day's filming.
When told she was not the star of the film, Marilyn was quoted as saying: "Well, whatever I am, I AM the blonde."
In her very last interview (10 years after making "Gentlemen Prefer Blondes"), Marilyn Monroe recalled the lack of respect studio execs had for her, but made a point of mentioning co-star, Jane Russell: "I remember when I got the part in 'Gentlemen Prefer Blondes.' Jane Russell, she was the brunette in it and I was the blonde. She got $200,000 for it, and I got my $500 a week, but that to me was, you know, considerable. She, by the way, was quite wonderful to me."