She once said that Celia Johnson told her that the way to get into character was to try and work out how the person walked. So, when she played Jemima Stanbury in the television adaptation of Trollope's He Knew He Was Right -- a phrase dear to every critic's heart - she imagined an immensely purposeful stride. As she told the journalist John Walsh, "I could see her walking with speed and precision, always talking at the same time." How brilliant is that?
She really did belong to showbusiness aristocracy. Her father was Raymond Massey, a most eminent and distinguished Canadian actor whose bloodhound features seemed to authorise any film he was in, while her Mancunian mother, Adrienne Allen, was in the original cast of Coward's Private Lives in 1930, making up the quartet with Coward, Gertrude Lawrence and Olivier.
We know quite a lot about her personal life: she was estranged from her brother Daniel Massey (who played Coward in a rather underrated film, Star, opposite Julie Andrews as Gertie) for many years, "came out" as a debutante in high society, was married briefly to Jeremy Brett, the best ever Sherlock Holmes on television (until Benedict Cumberbatch came along, of course), and found later-life happiness with a Russian metallurgist whom she met at a dinner party.
She was also, at various times, anorexic, insomniac, and often depressed, spending 12 years in psychotherapy but pulling through with a healthier diet and a plentiful intake of camomile tea. And she was a terrible cook.
But because she lived life so near the surface, this gave her acting a febrile, mercurial quality that was utterly transfixing, with great faun-like eyes that never seemed to blink, the sexiest hint of a lisp with slightly protruding teeth, and that voice - dry as sandpaper, as well as the martini, and as capable of sarcasm and withering scorn as of a more mellow sounding sweet reasonableness.
I'm half on holiday this week and looking forward to a few days on the Isle of Wight, but I revved up, as it were, last night, by going to see the remarkable documentary film Senna, about the Brazilian racing driver Ayrton Senna, who died in a crash on an Italian race track in 1994.
Senna won the Formula One world championship three times, had a marvellous long running battle with the more diffident and establishment-minded, politically astute French champion driver Alain Prost, and left a sizeable chunk of his great financial fortune - nobody knew this when he was alive - to the poor children of his native country.
But what the film does, dramatically, is convey a sense of tragic gloom and doom around Senna, who was probably the most driven driver of all time, utterly and precociously fearless, and a more interesting and extraordinary man outside of a racing car even than he was inside one.
It was clear, at the end, that he was unhappy about the Williams car he was driving on that fateful weekend, and his crash involved no other people. It's thought there was a fault in the steering. There had already been one serious accident and one fatality in the speed trials that weekend, and it was as though Senna embraced the inevitable as a dictate from God. He was intensely, and unswervingly, religious.
The adrenalin of fear is common to actors and athletes. They risk more than the rest of us and have, I'm sure, much harder lives as a result. I don't think Ayrton Senna became a superstar for the trappings, or because of the vanity involved, or because of the money. He became who he was because he literally had no choice.
And I think the same was true of Anna Massey, though she affected a diffidence that disguised the inner demons. With Senna, there was no disguise. And that's what made him a people's champion and one of the greatest of all mini-gods in the history of sport.