Monroe and Russell do a superb job handling comedy, both demonstrating what immensely talented performers they were. Charles Coburn is perfect in the kind of role he was born to play, as the easily confused, doddering old millionaire, and Tommy Noonan hits the right note as Monroe's long-suffering fiancé, playing the comic foil with just the right amount of sympathy. Elliott Reid is fine as Jane Russell's love interest, but he isn't given much to do with his role as the private detective hired to trail the girls to France. Hawks is the ideal director for this material, keeping the energy high and the jokes flying, and utilizing the lavish production values to full effect.
The highlight is the "Diamonds Are a Girl's Best Friend" number, performed by Marilyn Monroe in one of the most glittering, show-stopping numbers ever to come out of a Hollywood musical. It's a splendidly photographed sequence, with Monroe set against a red backdrop that pops off the screen. There is one particular moment during the song- when the backdrop switches from red to black, the action freezes, and a single spotlight shines down on Monroe - that will give you chills for its sheer power.
It's a quintessential Hollywood film of the '50s, and a perfect vehicle for two great screen icons.