I am sitting on a tiny orange chair. It has a tiny bucket seat and four tiny black legs. This chair would be tiny for an oompa loompa. I am not an oompa loompa and I am exceptionally uncomfortable. I have twisted my legs up and around and hunched my back to try to fit my 6ft frame into this tiny space.
Beside me a newly-fitted air conditioning unit blows Siberian gusts into my ear.
I cannot move or complain. The curtain is about to go up.
The pianist begins -- a few jolly notes -- and two young girls begin to sing earnestly to each other, only the faintest tremble indicating their nervousness. The tremble is amplified and broadcast around the big room, where rows of adults sit, tense and obedient as leg muscles start to cramp.
Guitars and drums now join the song, swelling the melody and only just failing to drown out the sounds made by excited ranks of small people being assembled backstage. The curtain bulges alarmingly then suddenly eases, disgorging a pod of children who take their place at the side of the stage.
And there is Grace, right at the front, singing like every line is a hallelujah, her face lit up with happiness. Her kohl-rimmed eyes are huge and as she turns to address the main players my breath catches at the beauty of her profile.
As she turns back to face the audience she sees me and without faltering flashes me a brilliant smile. Her make-up shimmers and sparks. She is the most joyful I have seen her for months.
Later on, Grace sings four lines alone, proud and sweet. She has practised them for days. It is her big moment but the microphone has not been set up and no-one can hear her. At the back of the room the music teacher flaps her arms in panic and the assembled parents, with the timing of old pros, obligingly join in the chorus. Grace is oblivious, her joy undimmed.
Later that evening I line up children in our bathroom and set about removing their stage paint. J, my elder step-son, is a cheeky tiger in elaborate orange, yellow and black stripes. D, my younger step-son is a mutely mortified wildebeest, daubed entirely brown so that the whites of his discomfited eyes gleam in stark relief. It takes several baby wipes and a douse under the tap but eventually I reclaim their sweet little boy faces.
With Grace I wipe and wipe and wipe. Carefully, over and over.
But nothing removes her sparkle.