Diane Sawyer's Final Sign-off on Good Morning America 2.05K Whitney Jefferson 12/11/09 11:59AM Filed to: TV TV Good Morning America Diane Sawyer Video Today marked Diane Sawyer's last hurrah on morning television. Watch her use up the last excuse to exercise zany, morning-show antics as she and the rest of the morning gang dance and sing along to "Build Me Up, Buttercup."