My Fair Lady
Daisy's story is below the poster.

Daisy assumed that the film would be shot in London when she auditioned for the role of the house cat for Professor Henry Higgins. Although she got the part, but she was disappointed to find out that the whole movie would be filmed on sound stages in Hollywood. Even the outdoor scenes were filmed indoors on the stages.
Her role was more of a cameo because she only appeared in scenes depicting the home of Rex Harrison's character. Harrison and Wilfred Hyde-White, who played Higgins' compatriot, were very nice and laid back, and filming with them was easy. Everyone got along remarkably well.
However, Harrison, who had recently given up smoking, was irritated that Audrey Hepburn smoked three packs of cigarettes a day.
Daisy had been in a musical before, West Side Story, and there were musical numbers in The Wizard of Oz, so she was used to the actors and actresses lip-synching their numbers. But that wasn't the case with Rex Harrison.
He couldn't sing, so he rhythmically talked his way through musical numbers as he had done on the Broadway stage. They couldn't lip-sync his talking, so he wore a wireless mic hidden in his tie and recorded his numbers during the actual filming.
That presented post-production problems because his mouth and words were perfectly in sync while the lip synching for everyone else was a little off. That difference was noticeable watching the film, so in post-production, Harrison's soundtrack was altered so his mouth and words were slightly off. As long as everyone's syncs were a little off by about the same, movie goers didn't notice when the film was released. Daisy's voice was not affected because she didn't need to move her lips to purr