Premise: Tabitha Anastasia "Tibby" Tomko-Rollins is a fictional character in the 2001 novel "The Sisterhood of the Traveling Pants" and the 2005 film based upon it. She is a member of the titular club, along with her friends Lena Kaligaris, Bridget Vreeland and Carmen Lowell. She was portrayed by Amber Tamblyn in the film.
Hypothesis: Lena Kaligaris, Bridget Vreeland, Carmen Lowell and Amber Tamblyn each portrayed the same character in the 2005 film based on the 2001 novel "The Sisterhood of the Traveling Pants", except Lena Kaligaris.