The lights are dimming in the big dining room at the Grosvenor House hotel as Marlene Dietrich wiggles onstage. At a table right at the front Elton John and I virtually have our heads in our puddings. We're not drunk. Folklore has it that Marlene's fabulously smooth face is due to her yanking everything back under a swimming cap and then shoving a wig on top and we're very keen to find out if this is true. The year is somewhere in the mid-70s and so is the age of Miss Dietrich.

You have to take your hat off to this game old trouper going through agonies in the head department and then pouring herself into a crystal-encrusted gown so tight she can only shuffle.

We have just eaten the sort of mass catering indifferent chicken course that's usually dished up for big events and the room is crammed for what will turn out to be one of Marlene's last cabaret performances. Also at our table is Elton's partner and manager John Reid, as well as their Surrey neighbours Bryan Forbes and Nanette Newman. I'm there because I'm Elton's press officer at Rocket Records. Heads horizontal we scrutinise, but alas there's not a telltale piece of hook or rubber to be seen – the old girl looks amazing.

Elton's in his duck outfit, mad feathers' phase onstage although in a sober suit tonight, but we all agree that even the windscreen wiper glasses are a doddle to perform in compared to the headache Marlene must be suffering. We go home full of admiration for the old diva.