Kelly Osbourne mourns loss of Amy Winehouse

Kelly Osbourne had planned to attend Kim Kardashian's wedding shower Saturday, but that all changed when she learned her longtime friend Amy Winehouse had passed away at the age of 27.

PHOTOS: Most shocking celebrity deaths

"I can't even breathe right now. I'm crying so hard," Osbourne, 26, tweeted. "I just lost one of my best friends. I love you forever Amy and will never forget the real you!"

1. More Entertainment stories
   1. Autistic ballerina dances her way into hearts
      

      In a popular YouTube video, the beaming little ballerina dances an entire four-minute routine seemingly perfectly, matchin...

   2. Every on-screen drink in 'Mad Men' in 5 minutes
   3. See the 'Dancing' stars' most memorable moves
   4. Emmy's biggest snubs? Cranston, Hamm, more
   5. 'Toy Story' toys burn up in prank on mom

When one Twitter user accused Osbourne of not doing enough to help Winehouse overcome her addiction issues, the E! personality fired back : "Are you f***ing kidding me? You have no idea what you are talking about! It would be in your best interest to shut the f*** up!"

PHOTOS: Stars we lost in 2010

(With the help of Winehouse's father, Osbourne famously helped the troubled singer check into rehab in 2008).

"I miss my friend," Osbourne added. "I'm going to be off Twitter for awhile. Thank you for all your support!"

PHOTOS: Other celebs who went to rehab

On Saturday, police found Winehouse lifeless in her Camden Square apartment. Pronounced dead on the scene, Metropolitan Police told Us Weekly in a statement that "the circumstances of the death . . . are being treated as unexplained."

Winehouse is survived by her parents, Mitchell and Janis, her older brother, Alex.