And Nate: [s1e13] The Thin Line Between Chuck

This episode marks the transition of Chuck and Nate's friendship from best friends to bitter rivals and Jenny's official entry into the "popular" group.

Jenny Humphrey, seeking to dethrone Blair, overhears the truth about Blair and Chuck. She is the one who confirms the affair to Nate.

Nate physically attacks Chuck on the street after learning about the betrayal. [S1E13] The Thin Line Between Chuck and Nate

Serena was actually buying the test for Blair, whose period is late. While the test ultimately comes back negative, the fallout is permanent.

Serena is spotted at a drugstore buying a pregnancy test, which immediately becomes a Gossip Girl blast. This episode marks the transition of Chuck and

by The Pussycat Dolls (Nicole Scherzinger) during the final emotional scenes. "Got Your Number" by Nadia Oh. "Where There's Gold" by Dashboard Confessional.

Look out for the classic UES school uniforms and Eleanor Waldorf's concern over Blair's behavior, which hints at her past struggles with bulimia. Notable Soundtrack: Nate physically attacks Chuck on the street after

Distraught by the pregnancy rumors, Dan blurts out his love for Serena in a panic. He later tries to redo the moment with a romantic picnic, but it is derailed by a Gossip Girl blast. The Betrayal: Chuck vs. Blair vs. Nate