What did Blake Lively do for her 21st birthday? She celebrated while working of course! Blake was seen on the set of Gossip Girl doing a little bit of work and play.

When she walked from her set to the trailer, the paparazzi sang Happy Birthday to her. Now that tells you what a good relationship she has with them! She started laughing and smiling. After she finished up her work day, the paps saw her carrying birthday gifts, one which was a Martha Stewart cookbook.

Overall, it looks like Blake had a fun day! Let’s hope she got to spend some of it alone with boyfriend Penn Badgley!

More pictures of the birthday girl after the jump.