VIDEO : Taylor Swift Celebrates Karlie Kloss's Birthday In The Hamptons

Talor Swift celebrated her best friend Karlie Kloss's birthday over the weekend in the Hamptons. The 26-year-old singer joined Nelly on stage at some point during the party to accompany him on his hit song, "Dilemma." Swift was wearing a black off-the-shoulder crop top with a matching skirt. Sources say that Swift's new beau Tom Hiddleston was not present at the b-day bash. Other celebrities in attendance included Chris Rock, Heidi Klum, and Leslie Odom, Jr.