Stars React to DJ AM's Death

As the news of DJ AM's shocking death Friday afternoon in New York ripples through the world, his many famous friends and fans have already gone online to express their sorrow at his sudden passing.

John Mayer Tweeted: in complete shock

Ashton Kutcher wrote: much love to my boy am

Kelly Osbourne expressed her horror: I just can't believe Adam is gone, I dont wanna believe I'm in shock. he is one of the most genuine people I've met.

Lindsay Lohan Tweets: i can't believe this , im in shock, why> whiy ? r.i.p adam

Khloe Kardashian wrote: Tell your loved ones you love them every chance you get. You never know when it will be the last time. God bless DJ AM. I love you

Katy Perry says: rest in peace friend.

And Emmy Rossum said: RIP AM...you were love and respected and will be missed