Adam Yauch aka MCA of the Beastie Boys dead at 47: Celebrity reactions

17 of 20: Will.i.am expressed his sadness over the loss of Beastie Boy member MCA.

'#restinpeaceMCA 1 of my favorite hiphop groups...hiphop raised a lot of us & now we have to wake up because are hero's are dying too younge,' he Tweeted.

(Pictured: Will.i.am appears in an undated photo posted on his official Facebook page.) (Facebook.com/william)