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Project Runway season 4 winner Christian Siriano is back with a new maternity collection, and it’s his fiercest yet. Siriano’s Spring 2010 Fierce Mamas line, his third for the Moody Mamas brand, features playful party frocks, feminine details, eye-catching patterns, and ultra-wearable jersey Ts and dresses. “It’s about making it really, really wearable, accessible and still really comfortable,” says the designer, who also has his own namesake ready-to-wear label and a shoe line for Payless. His must-haves for great pregnancy style? “A great T-shirt and a signature party dress,” Siriano tells PEOPLE. “When you’re pregnant you still do the same things that you would normally do — go to events, baby showers and weddings. Not every brand does sweet, fun party dresses like this.” While his celeb fans already include new moms Ashlee Simpson-Wentz, Heidi Klum and Jessica Alba, Siriano says he hopes to some day design for his dream client: “Drew Barrymore, because she’s so chic and fun and so interesting fashion-wise.” Fierce Mamas for Moody Mamas by Christian Siriano ranges from $50 to $250 and will be available this spring at moodymamas.com. Check out Christian’s entire Q&A at celebrity-babies.com. –Nina Tyler