Vest with a dress?

[Aparecium]

I'm really tempted by this dress, but there's no way I'm going bra-less. Would I totally ruin it if I wore a camisole or vest underneath?

Allegra Ring Dress Teal (monsoon.co.uk)

No of course not. I'd wear that with a very plain stretchy lycra vest like the sort you get in TK Maxx

I'd go for something like the ultimate plunge bra from wonderbra instead