VALENTINE’S PLANS: It could have been the fact that it was Valentine’s Day, or that the weather was warm and sunny, but the front row at the Monique Lhuillier show was all smiles at 3 p.m. at Lincoln Center. Lauren Remington-Platt, Jay Alexander and Julia Stiles were all on hand, and couldn’t have seemed happier. Stiles had changed ensembles from her last front row appearance earlier in the day. “I know, I’m silly. I had to do it once, though. I was hoping no one would notice,” she said with a laugh. She sat next to Brittany Snow who enthused, “It’s fashion week, it’s exciting!” Alexandra Richards, who was dressed down and wearing her specs, has been busy working this week. She DJ-ed the Jill Stuart show, with more to follow over the next few days. Was she headed out tonight? “No, it’s Valentine’s day...I don’t know what my plans are, I didn’t make any, but I hope my boyfriend did because I cleared my schedule!” Here’s hoping her DJ beau Nick Cohen came prepared.