'Riverdale' is celebrating 100 episodes! Grab your favorite milkshakes and get ready for a trip down memory lane because only ET has exclusive interviews with entire cast looking back on the show's sweetest moments. From their favorite memories filming the pilot to the series' most romantic scenes, KJ Apa, Cole Sprouse, Lili Reinhart, Camila Mendes and more stars of the hit drama are spilling it all. Plus, Madelaine Petsch, Vanessa Morgan, Casey Cott, Charles Melton, Drew Tanner Ray and Erinn Westbrook are revealing which couples they're still shipping after 100 episodes of heated moments, heartbreaks and love triangles. The 100th episode of 'Riverdale' airs Tuesday, Dec. 14, at 9 p.m. ET/PT on The CW.