One of Michelle Obama’s favorite fashion designers, Jason Wu, began his obsession with styling at a young age by working on his collection of Barbies. “I would buy Barbies and take them apart and then remake their looks,” Wu recalls in the latest issue of Interview magazine out today. “I used them for hairstyling. It was a whole process. I had a lot of dolls — like 150.” Wu also says RuPaul was another early inspiration. “I thought that he was a she,” Wu explains. “Later, of course, I found out that it was a man. But he was so tall and glittery and impressive, with the big hair . . . You know, a fashion-obsessed boy would be into that.” He’s come a long way: Wu last week hosted a glittering bash for Young Friends of ACRIA to benefit AIDS research, for which he created a limited-edition T-shirt with artist Nate Lowman. Guests included Diane Kruger and DJ Harley Viera-Newton. .