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Nicole Richie is already in fine form, but a few extra workouts before her December wedding certainly can't hurt!

We snapped the bride to be leaving the gym in Studio City yesterday afternoon, and with less than a month to go until she walks down the aisle with Joel Madden, you can bet the hot mama is busting her booty on the treadmill. We definitely can't wait to see her wedding dress -- think it'll be one of her own designs?