Mrs T sets her cap at Mr Astaire

Mrs T, as always, is approximate:
Dear Mr Astaire, she writes, what a tragedy that your knees are going just when you were beginning to build up a reasonable dancing career. I can understand what a blow it must be to you, seeing that you can't act for toffee.
Also, I didn't realise until now that you were Hungarian, though it probably accounts for your lovely legs, what with all that Hun horsemanship, killing Slavs and so on. I often wonder what it must be like to grip a huge horse between one's thighs....
Anyway, I don't wish to protrude on your privates, but I really would like to know what it was like to dance with Ginger Rogers. She seemed such a skinny thing, not a bit like the plump Welsh girls you could have got your hands on if only you and I had been in touch sooner.
Don't make it so long next time.