Blake Lively is celebrating her “forever sister” Amber Tamblyn’s birthday.

On Thursday, Lively posted a sweet photo of her and Tamblyn with their “Sisterhood of the Traveling Pants” co-stars to her Instagram Story to mark the actress’ 37th birthday.

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“Happy Birthday my forever sister,” she wrote on the photo.

Instagram/blakelively
Instagram/blakelively

Tamblyn also took to Instagram to re-post the photo saying, “Love you sis. Truly.”

Instagram/amberrosetamblyn
Instagram/amberrosetamblyn

Lively is not the only celeb to wish Tamblyn a Happy Birthday. Amy Schumer and Eliza Clark were also among those celebrating the star.

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Instagram/amberrosetamblyn
Instagram/amberrosetamblyn
Instagram/amberrosetamblyn
Instagram/amberrosetamblyn

Lively, Tamblyn, Alexis Bledel and America Ferrera have remained close since co-starring in the “Sisterhood of the Traveling Pants” movies together 15 years ago.

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