The other two women in the dressing room had attended balls at the White House on many other similar occasions, but this was my first time.

I had no say in my outfit. It was delivered with the gowns for the other two women by a White House aide. When I unwrapped the tissue paper I found a beautiful slim long skirt festooned in thousands of dull metal sparkling sequins, and a sleeveless top in the same material. Then I spotted the label – size 7 – and worried that the two garments would not fit. One of my companions, who was busy unwrapping a blue dress of her own, explained that a US dress size 7 was a UK medium and that my outfit was just the right size for me.

I tried it on and it looked great – apart from the shoes. I was not going to risk falling over on the red carpet so insisted on wearing my everyday clumpy black footwear with my sparkle dress.

I wondered whether we would be allowed to keep our new outfits after the ball.