What to wear to a surprise party?

[FancyCatSlave]

Going to a surprise 70th party in early May. Being held at someones house and starts 4pm and will go on until about 10pm I think (not sure exactly).

Not sure how dressy vs casual to pitch it. I’d probably wear a dress. A 4pm start has thrown me off a bit.

I always think the style of Alemais clothes is perfect for day into evening parties:

https://alemais.com/collections/clothing?page=57

and places that offer similar looks at less elevated prices might include:

Essential Antwerp
Free People
Mango
Plümo
Toast

Those dresses are beautiful