Beastie Boys rapper MCA - real name Adam Yauch - has died at the age of 47.
The star was diagnosed with cancer in 2009, although the BBC is reporting that it is not clear whether his death was connected with the illness.
Twitter has been paying its tributes.
'Such sad news about Beastie Boy Adam Yauch. A fellow Buddhist and part of hip hop history!! R.I.P!'
B Real Cypress Hill (@B_Real420)
'My deepest condolences 2 the family of Adamyauch & the beastie boys. Adam was the coolest dude ever & will b missed but memory will live on'
Dr Strangelove (@IMissThe1990s)
'So happy I got the chance to see the Beasties in 07. they were more than just a hip hop group. And AdamYauch was much more than just an MC'
'AdamYauch, thank you for helping shape cooler people. Your journey here looked and made fun. What a gift'
Duran Duran (@duranduran)
'Rest in Peace AdamYauch. Our condolences to your friends and family'
'So sad to hear of the passing of AdamYauch. A true legend and co-founder of a game-changing musical act'