what will you wear to our party? A 1930s vintage dress would be great but perhaps not readily accessible. However, there are lots of modern dresses availble that are made in the style of the 1930s/1940s etc, so why not try one of those? Inspiration is readily available on the web but a good start is Vintage Dancer. This is an american site but has good advice on the style and trends of the time. Follow this link vintagedancer.com/1930s/women-1930s-fashion/
Searching the shops or the web, you will find more choice of 1940s style dresses than the 1930s. Fortunately the styles are similar so 1940s dresses will be okay; we won't be operating any fashion police at the party!