Mary-Kate and Ashley Olsen open up in this exclusive video about their latest venture Stylemint, a social shopping site that sends you a new tee (designed by the duo) based on your personal style profile for $29.99/month. We follow them behind-the-scenes as they shoot the imagery for the line with photographer Terry Richardson and model Tati Cotliar.

Photographed by Terry Richardson

Here's a sneak peek at the first graphic tee designed by the Olsens.

for a chance to win one, read below:

To enter, leave a comment below telling us what you think of Stylemint and your t-shirt size.

Or, use the button below to tweet and let us know what you think of Stylemint and your t-shirt size.

This giveaway is open to legal residents of the 50 United States, the District of Columbia and Canada (excluding Quebec) who are 18 and older. Comments and tweets must be left before 11:59pm ET on July 15th, 2011. You may enter only once and two winners will be selected at random to win either one small or one medium Stylemint t-shirt valued at $20. Click Here for complete Official Rules.