We know - you wish you had trained in the gym a little harder, stopped eating chocolate a little sooner or given up sugar a little earlier.
There are some changes you can make at the very last minute - we're talking days - that will make a difference.
According to celebrity trainer Dalton Wong, he lends these same tips to all of his celebrity clients (including Amanda Seyfried and Alice Eve) ahead of any red carpet moments, when their body is under the spotlight.
Seven steps to boosting your body confidence:
1. Cut out Salt
"And that includes any foods, sushi being a major culprit, that contains salt too. It holds onto water so you look more puffy."
2. Don't Eat Raw Vegetables Late at Night
"They take a long time to digest and can leave you looking seriously bloated, so if you are going to eat them, have them earlier on in the day. Other foods that increase bloating include wheat, lentils and beans - they just make your stomach look much bigger."
3. Lower your complex carbs
"For every gram of complex carbohydrate you'll hold on to three of water, so if you can cut them out. Complex carbs classically take much longer to digest and include wholemeal bread, cereals and whole grains. Plus, depending where you are on your cycle the effect can be ten fold."
4. Sleep more
"Before the big reveal, or event, get plenty of sleep to regenerate and recuperate. There's no point in a heavy workout the day before, it's just like cramming for a test, and will leave your body feeling and looking tired and hunched."
5. Focus on Posture
"Try to focus on stretching exercises the day before, Pilates and yoga are excellent as are any moves that pull the shoulders back and pull the lower abdominals in. Just remember that in the run-up you do need to be working on strength and posture together though. Models loves Pilates and yoga, but they never look like strong, instead they look like they're going to fall over quite frankly. On the flipside men who workout too heavily look hunched and rounded, so you need a balance.
And if you're flying somewhere as soon as you're off the plane go for a walk, or if you can, book in for a lymphatic massage, it stops the legs suffering from tightness and water retention."
6. Stick to the norm
"Don't eat, or exercise, out of the norm. Stick to what you and your body know. And don't under eat, you need energy to stand tall, which automatically knocks ten pounds off."
7. Hydrate, hydrate, hydrate "Making sure you're well hydrated is super important. If you're not, the body and muscles look almost tight and clenched. Don't over drink either - if you're going to the loo every hour that's not right, what you're looking for is about every three hours, and urine should be pale. Herbal teas are a great way to up your hydration levels as they also can have the added benefit of de-bloating or aiding digestion too. And it's a given, but do avoid alcohol."