All eyes were on Ines de Ramon at the San Sebastian International Film Festival Wednesday night. The jewelry exec supported boyfriend Brad Pitt at the premiere of his new movie, “Heart of the Beast,” dressed in a show-stopping green lace gown. With its sheer construction, skinny cross-back straps, low back and plunging neckline, the style was a sultry choice for the Spain event. Her hair was pulled back into a loose updo, and she wore no jewelry besides a single pinky ring on her right hand. Pitt, on her arm, chose a black three-piece suit with a crisp white button-down as they walked the red carpet together. De Ramon also accompanied…