Saying goodbye to our fierce advocate
pop star twerks during segment
the pop star twerks and spills secrets on the segment
the show raised $7.5 million
celebrities give back during holiday season
tweets range from humor to sadness
the pop star sang 'Imagine,' 'Like a Prayer' and more
singer thinks the two musicians are 'very different'
Madonna, Anderson Cooper among star donors
the singer jokingly begged voters to support the Democratic nominee
