Gwyneth Paltrow hopped on a bike to film Thanks For Sharing in NYC this afternoon. She changed into a black Stand Up 2 Cancer shirt for another scene with costar Mark Ruffalo after the duo started working together on set this week. Gwyneth made the trip to the East Coast from the UK on Sunday, and she was spotted at the airport with pal Cameron Diaz. The stylish girlfriends partied at The Arts Club and celebrated pal Stella McCartney's birthday during their time in London. Gwyneth may be back to work, but it looks like she's having a great time on set since she tweeted "Shooting in sunny central park. Reminds me of my youth." and was also spotted sharing a laugh with Mark. He's a little more serious in the new trailer for The Avengers, which gives fans a quick glimpse of him in character as The Hulk.