It was a long time coming. The season's first perfect 30 was finally awarded on Dancing with the Stars last week. " Jennifer's Body [Grey] and I really couldn't believe it, especially for the Instant Dance," Derek Hough tells  "I was so proud of her and I'm so impressed. It was a tough week. We were waiting for the doctors to give her the green light for her knees, and they did, and she just killed it." The Dirty Dancing star's injuries and doctor visits have been well-documented — perhaps to a fault, Hough says.