Patricia Arquette
Credit: Kevin Mazur/WireImage

Patricia Arquette took home the Oscar for Best Supporting Actress for her role in Boyhood, and InStyle grabbed her backstage to get the scoop on her gorgeous black-and-white Rosetta Getty gown.

"I'm wearing a dress that my best friend designed—we've been best friends since we were seven and eight years old," Arquette said during the backstage press conference. "And she was the first person who said to me, 'What do you want to be when we grow up?' We were standing next to her Barbie Dream House. And I said, 'I want to be an actress. What do you want to be?' And she said 'I want to be in fashion—I want to be a fashion designer.' And she designed my gown, so it's like wearing love."

The actress and Getty started a sweepstakes this morning for their charity, "I never saw this moment of me winning an Academy Award. I never even thought I'd be nominated—and I was okay with that," Arquette said. "But you know what I did see? If there was anything I did want to have come true in my life, it was that I would help thousands of people. And I have and I will. I will help millions of people."

—With reporting by Scott Huver