wearing actual lingerie under a dress at the formal dinner of a lifestyle resort week, too much or completely standard

so weve booked our first proper lifestyle resort week (lates 30s, perth australia, will be on the gold coast for a takeover week at a small adults only resort). about 40 couples for a week. theres a "formal dinner" night about halfway thru the week which is described as black tie ish, dinner first then "transition" into the play areas, etc. ive bought a lovely long black dress for the dinner. nothing crazy, classic, fits properly, would not look out of place at any nice restaurant in any city. but ive also bought a proper set of lingerie underneath (bordelle, cost a fortune, i love it) and im now in this little crisis of "am i meant to wear lingerie UNDER my dinner outfit on the dinner night, or is the play kit a separate thing you change into after dinner". like is the move to be wearing the kit all thru dinner so by 11pm when ppl start drifting into the play areas im already in it, or do experienced women change properly between dinner mode and play mode. aussie women in particular who've done these weeks before, whats actual practice. i dont want to be the one woman who turned up in undies under her dinner dress while everyone else is wearing normal undies and changing in their rooms after the meal. but i also dont want to be the one woman in normal undies wondering why everyone else is half dressed an hour earlier than me. the resort itself was a bit vague on this in the welcome pack