full size Leighton Meester Wears a Red Hat to Support Blood Cancer Research at a Yankees Game on August 4, 2012
Credit: Leighton Meester on Instagram

Leighton Meester is best known for being Gossip Girl's reigning Queen B, but did you know she's a total do-gooder at heart? Leighton is an active supporter of blood cancer research, and she never passes up an opportunity to campaign for awareness.

This superstarlet hit up a Yankees game over the weekend, and tweeted "Wear your red hats, Yankees fans! #deletebloodcancer," along with an adorable pic of herself and her buddies. Awww, what a gal!

Not only did Leighton recently teamed up with DKMS in the fight against blood cancer, she also encourages her fans to "get swabbed," donate blood, and help save lives. Go for it, Gossip Girls!

Source: Leighton Meester on Instagram

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