“You are in love, true love,” Taylor Swift, 33, sings on her 1989 deluxe track, “You Are in Love.” The song, which was co-written and produced by Swift's frequent collaborator, Jack Antonoff, 39, would've been a fitting anthem this past weekend, when Antonoff tied the knot with actress Margaret Qualley, 28, at an intimate ceremony in Long Beach Island, New Jersey. Swift, of course, attended the ceremony, which was chock-full of other A-list stars.