How can I reduce bloat on my stomach for a party tonight? 10PTS!?

I woke up and had a glass of water, half an apple and 5 almonds. This was to give me energy for my short workout, which was a 15 minute jog on the treadmill and 10 minutes on the stationary bike. I then went to the sauna. After, for breakfast I had oat bran made with water with half a cup of decaffinated tea. For lunch I had half a cup of decaffinated tea, 100g of melon (cantaloupe) and a tiny bowl of about 25g probiotic yoghurt and 10g of muesli (just a small tiny craving I had).

I've had about 6 glasses of water today, and I will continue to drink even more. I will have a very early dinner at 4pm, which I was thinking to have a grilled chicken breast, grilled tomato and a grilled large flat mushroom.

Is there anything else I can do to reduce my stomach for tonight? As I woke up with a super flat tummy this morning and I want that back!!