Stunned Celebrities mourn Whitney Houston

The sudden death of singer Whitney Houston at age 48 shocked fans and musicians all over the world. The outpouring of grief was immediate, with one common refrain: The world had lost one of its greatest singers.

Nearly all of the trends on Twitter worldwide were shortly associated with the singer's death: R.I.P Whitney Houston, #DearWhitney, #IWillAlwaysLoveYou, The Bodyguard, Bobby Brown and Wanna Dance With Somebody.

"The first full hour after the news broke saw 2,481,652 tweets and retweets, peaking at 61,227 tweets at 5:23 p.m. (all times are PST)," according to Topsy.com, which indexes and ranks results based on the most influential conversations on social media

"That is over a thousand tweets a second, not quite as much as during the Superbowl but still a lot."

Beyonce Knowles

"The loss of Whitney Houston is painful. I remember meeting Whitney for the first time when I was 15. She was the ultimate legend. The ultimate woman. Not only was she confident, poised, stunningly beautiful and intelligent, but she was sincere and kind. She took the time to make everyone feel like they were very important to her. I, like every singer, always wanted to be just like her. Her voice was perfect. Strong but soothing. Soulful and classic. Her vibrato, her cadence, her control. So many of my life's memories are attached to a Whitney Houston song. She is our queen and she opened doors and provided a blueprint for all of us. God bless her. "

Celine Dion:

"I'm in shock. Whitney was such an amazing artist. When I started my English career, I wanted to be like her. I loved her so much. My prayers go out to her daughter and to all of her family."

David Foster, producer:

"There is not a word that describes my reaction... It doesn't exist in the English language.. .This was the voice that record producers dreamed of working with... I got butterflies.. She was pure magic. She was iconic ... I had the  pleasure and privilege of having an up close and personal front row seat  to the greatest of them all."

Christina Aguilera:

"Whitney's voice was so special to me. Her notes soared to places most singers dream of reaching. She will be missed."

Kelly Rowland:

"I am beyond heartbroken. Whitney Houston was undoubtedly one of the greatest singers and performers of all time and such a huge influence on me."

Mariah Carey:

"Heartbroken and in tears ... My heartfelt condolences to Whitney's family and to all her millions of fans throughout the world. She will never be forgotten as one of the greatest voices to ever grace the earth."