Regular music fans and superstar performers joined together in a chorus of grief Saturday night upon hearing that Whitney Houston had died at age 48 on the eve of the Grammy Awards.

"You are the reason I fell in love with singing. My heart is broken," tweeted Grammy-nominated Toronto singer Melanie Fiona.

"I'm really not okay," wrote Fiona, who is up for best traditional R&B performance at Sunday's ceremony for her Cee Lo Green duet Fool for You, which also earned a nomination for best song.

Fiona summed up the impact of Houston's death on her with one word: "Devastation."

Police said Houston was pronounced dead at 3:55 p.m. in her room at the Beverly Hilton Hotel, where the singer had been scheduled to perform at the annual Grammy party held by the man who discovered her: legendary music producer Clive Davis.

Online tributes

Word of her death — the cause of which was not immediately known — prompted a torrent of tributes on Twitter.

"One of the GREATEST VOICES EVER just passed," tweeted teen sensation Justin Bieber. "RIP Whitney Houston. My prayers go out to her friends and family."

'Despite her controversy, her voice... has defined music today.'—Lady Gaga

Canadian rapper Wes Williams (formerly known as Maestro Fresh Wes) recalled Houston's stunning looks.

"Crazy. Whitney was my first celebrity crush and set my standard for Black women's beauty," Williams tweeted.

Toronto rapper Drake, who is up for three Grammys on Sunday, was succinct: "RIP Whitney Houston."

Personal problems

Lady Gaga hinted at Houston's personal problems which, in addition to addiction issues, also included a tumultuous relationship with ex-husband Bobby Brown.

"Despite her controversy, her voice... has defined music today," tweeted Gaga. "A true legend."

The news broke as Rihanna was rehearsing at the Staples Center, where the 54th Grammy Awards are set to take place. The death of Houston, the daughter of soul singer Cissy Houston and niece of singer Dionne Warwick, is sure to change the ceremony considerably.

Fans in the streets around the arena were grief-stricken.

Nancy Turpin of Chicago heard the news while browsing the Grammy museum.

"It's shocking. So shocking. She finally seemed to be turning it around."

Andy Bigelow, 44, of Chicago, said he had been a Houston fan since the 1980s and loved that she supported the gay community.

"The Grammys should end with her performance of the national anthem at the (1991) Super Bowl," suggested 37-year-old Karim Azeez of Los Angeles.

Los Angeles resident Walter Jones said he hoped the singer was in a better place and that the Grammy show would feature some of her hits, which include "Saving All My Love For You" and "The Greatest Love of All."

"She was especially important to me growing up as a black man," he said.

Party held as scheduled

Over at the Beverly Hills Hilton, the Davis event went on as scheduled. It was a bizarre scene as stars walked the red carpet amid a heavy police presence while news vans snaked around the block and paparazzi staked out every hotel exit.

At least one fan felt the gala should have been scrapped.

"It seems completely inappropriate that they're having a party while she's upstairs, deceased," said Adonis Ellis.

Katie Wage, a guest at the Davis party, could scarcely take it in.

"It's so surreal because she died here, only hours ago. I just can't believe it."