hallepartysupply460.jpg Planning a gathering, Ms. Berry?!

Halle Berry and her fiance Olivier Martinez stopped by an LA store today to pick up party supplies, and we can't help but wonder who she's throwing the big bash for! It's not daughter Nahla's birthday, and it's not her hunky French beau's either, so maybe she's a room parent at school?

Celebrating something is the last thing we expected the Dark Tide actress to be doing, considering she just lost her huge custody battle with ex Gabriel Aubry! The judge ruled that the 46-year-old will not be able to permanently move to France with her daughter, as it would impede regular visitation with the Canadian model.

We guess she could be throwing a "Staying in L.A" fete!