English Idiom: The genie is out of the bottle
Imagine you try to have a surprise party for your brother’s birthday. You want to keep it on the down low, but when his girlfriend accidentally tells him – the genie is out of the bottle.
You may hear this expression when a secret is not a secret anymore or when a change that cannot be stopped has begun.
You cannot make your brother forget his surprise party because once something is known, it cannot be unknown.
It’s more traditional to have genies in lamps, but English and English expressions change with the times. Now genies are in bottles not lamps.