Sienna Miller teamed up with Naomi Watts at the inaugural Up2Us benefit gala in NYC yesterday. The look-alike stars posed together on the red carpet for the charity, which aims to stop violence through youth sports programs. Erin Heatherton also attended the event, which took place at the Tribeca Rooftop. It's been a busy week for Sienna, who has been staying in the city with her fiancé, Tom Sturridge, after his play Orphans closed on Broadway last month. She joined Tom at the Theater World Awards in the Big Apple on Monday and she'll host a screening of her new film, Just Like a Woman, at the Crosby Street Hotel today. Sienna's new project is slated to hit theaters on July 5.