Loose 10 pounds with my body?

I am 18 years old, 5'7'' and weigh 128. I'm in entertainment so i've bee asked to drop around 10 pounds so that would be 120 minimum. What is a good diet / workout regimen for me? I can't do big weight cause I have to loose measurements. My thighs aculate the most muscle and fat. I can go to the gym 5 times a week. Thanks! Hope someone can help! :)