I remember her being directed by Samuel Beckett at the Royal Court Theatre in London (he’d invited me to a rehearsal of Happy Days). I was the only one in the audience. It was very intimate, nobody else was there in the theatre.
Beckett directed her like a musician – every single nuance of pronunciation of the words, articulation of the sentences was rehearsed in detail, with the same precision that a good conductor has regarding attack, rhythm, tempo, relative volume, pace.
When I attended the complete performance, I was struck by the different colour of Billie Whitelaw’s voice throughout the second part of the play, a change of timbre which was so effective that it continues to intrigue me musically in all sorts of ways.
At times you can hear something similar in great pianists, who can completely change the timbre of a quiet piece they are playing, by a subtle control of touch.