Lovely people, not posh or showy, but well off. We have known them a while as friends of friends, but not done a lot of socialising. Last time we met them at someone else's house (informal supper), I think she wore lightweight jeans and pretty top.
What would you wear to this sort of event? I feel a bit uncomfortable going out in jeans in the evening, would normally wear a pretty skirt and low key top, but I am ancient and out of touch!