The Hilarious Way Amber Tamblyn Found Out That Blake Lively Gave Birth

Blake Lively might be a new mom, but she is clearly a seasoned trickster.

“That bitch! She tricked me!” Amber Tamblyn told PEOPLE about how she found out that her Sisterhood of the Traveling Pants costar had given birth.

Sisterhood's Alexis Bledel

Alexis Bledel has been a busy Gilmore girl this year. She had a big screen turn as a prostitute in Sin City this spring, and stars as the soft-spoken artist Lena in The Sisterhood of the Traveling Pants, the new movie based on the bestselling teen novel. Bledel, 23, recently spoke with PEOPLE about empowering the girls and confusing her cat.

Do you have a lucky pair of pants?
I’m not too superstitious. I’ve had a few friendship bracelets, but for me, now I try to let go of things I don’t need anymore. It’s all about streamlining now.

Celeb Spotlight: Amber Tamblyn

Age: 22
Hometown: Santa Monica, Calif.
Current gig: Playing the rebellious teen Tibby, one of four best friends in the movie The Sisterhood of the Traveling Pants