American Eagle is so square. Next Thursday, the cargo short and denim haven opens its brand-spankin’-new Times Square flagship location (1551 Broadway; 212-205-7260), complete with a “denim library” stocked with more than 20,000 pairs of jeans and a “bra conservatory” featuring more than 7,000 bras. Haute List has the scoop on Tuesday night’s opening party. We hear that Gossip Girl Leighton Meester is providing the entertainment — she’s scheduled to sing — and that she’ll be performing “Good Girls Go Bad,” “Somebody To Love,” “Playing Games” and “Your Love’s a Drug.” Word on the street is that Fall Out Boy’s Pete Wentz will deejay. Plus, the first 10 Haute List readers to e-mail email@example.com will receive a limited-edition tote bag ($29.50) and the brand’s chic sequin cardigan, (pictured at right) (normally $89.50) for free!