When William Rast co-founders Justin Timberlake and childhood friend Trace Ayala brought in husband-and-wife design team Marcella and Johan Lindeberg last year, the venture became even more like an extended family. “We talk about everything. Justin is even baby-sitting our daughter,” says Marcella from backstage at the line’s debut show at Bryant Park. “We have a style that we all like. The foundation is there.” And Justin and Trace have just as much of an understanding. Says Timberlake, “We inspire each other. For instance, this season, we’re inspired by Barack Obama. I am inspired where we can go with the nation. That’s why we picked the theme of New America for the show.” Timberlake’s girlfriend Jessica Biel is “so proud” of the direction they’ve taken. “They’re clearly taking it to another level. I want the whole line,” says the actress, who often test-runs the clothing. “I always wear the stuff and say, ‘This is tight here. Or this doesn’t work for me here.’ I’m sort of a guinea pig, really.” Even their moms are in awe. “We came from a small town in Tennessee. And our kids are doing a fashion show at Bryant Park. What happened?”