The star-studded birthday bash was held at Jimmy Iovine and Ross' Malibu home, reported Us Weekly.
"Gwyneth Paltrow was dancing with Taylor Swift and hanging out with her a lot. They seemed like good friends. Taylor was in an amazing mood and very social," a source said.
Swift also debuted her new haircut from stylists Gareth Bromell and Tracey Cunningham at the party.
"She spent much of the night in the photo booth. Taylor was also busting moves with Mary J (Blige) on the dance floor for a while," another source added.