Present dilemma - what would you do?!?

[Oobleyyy]

DD1 told her sister what her present is vaguely (it’s a big Sylvanian Families set) but didn’t tell her which one. (The fact that DD1 told her is another story altogether!)

DD2 is going absolutely nuts. Begging me to tell her, saying things like “if you don’t tell me I’ll hate you” or “if you don’t tell me I’ll look for it anyway” etc etc on and on and crying (she’s almost 5). She won’t let it go!

I’ve been very gentle about it, telling her I understand how frustrating it is knowing there’s an amazing present in the house but not knowing what it is, etc etc. That isn’t working one bit.

DH thinks we should take it back and get her something completely different so that the torture is out the house.

DD2 is not letting this go. She’s ruining it for herself, really.

What do I do?!?!?

I'd have brazened it out and played dumb, said DD1 has got it totally wrong as Santa doesn't come for another few days!

Beyond that I'd tell her if she doesn't be quiet about it, she won't be getting it. I have a child of 5, no way would I cave in to pure brattiness.

Sorry op but both your children sound like brats to me the older one for telling the younger one and the youngest behaving like they are is just wrong.

No way on this planet would my 5 year old talk to me or behave like yours is doing.

I’d tell them that they need to calm down and have the present removed from the house.

Like others have said, giving in is missing an opportunity for children to develop much needed emotional regulation. It's not impossible to talk this through.
Some conversations I would be having would be
DD1 - Letting her know she has spoilt the suprise, this is not in the nature of Christmas or gift giving (unless otherwise agreed), it is not okay and she is not to do it, either within family or something socially. Explain how upset her sister is, how it could upset someone else - some people love surprises. she has made a mistake etc but that everything is ok. Apologise to sister.
DD2 - issuing unkind threats is hurtful and won't be tolerated. Explain at the same time you understand why she is upset, her sister made a mistake in telling her (note to her the chat you have had). Discussion of how it made her feel, if she can't verbalise it, you can give it some damn good explained guesses, that show her you understand the frustration. Explain that sister doesn't know which set it is, that there is no need to feel any competition that she knows and she doesn't kind of thing.
It is Christmas time. She is very lucky to be receiving Christmas presents, and that the basis of Christmas is that you don't know what you're getting. explain this is a very lucky experience that someone that loves you has chosen presents for you. She isn't to go looking for presents as it's disrespectful of yours and Santa's time.
Be firm and if screaming starts, walk away.
I can't see any harm in instilling reasoning, explanation and expectations of basic levels of respect for one another. Nor making consequences.