Coward wrote in his diary that Colbert was "extremely tiresome" during rehearsals, not arriving at the first rehearsal knowing the words, being "exceedingly bossy", insisting on only being "photographed on one side of her face, so all grouping of scenes has to be arranged accordingly", constantly changing her mind over her dresses, and being "determined to play Ruth as a mixture of Mary Rose and Rebecca of Sunnybrook Farm, and very, very slowly.
He thought Bacall "is charming and no trouble; also, unfortunately, no comedienne, but she moves beautifully, looks ravishing and is trying like mad".
He wrote Mildred Natwick "is wonderful: true, subtle and hilariously funny without ever being in the least grotesque".
[1] Coward's leg was in great pain during rehearsals, requiring him to take injections of novocaine to get through it.
He clashed with Colbert and was dissatisfied with a pre-show recording he did of the production.