Reese Witherspoon Red Dress Pictures at Late Show

Reese Witherspoon was just one of the lovely ladies to appear on the Late Show in NYC yesterday. She stopped by in a bright red dress to promote This Means War and shared a funny story about having to explain the term "d-bag" to her mother. David Letterman also welcomed Sports Illustrated's newest swimsuit cover girl, Kate Upton, and her fellow models. The 2012 Swimsuit Issue was unveiled last night while Reese's romantic comedy hits select theaters today — both just in time for Valentine's Day!