From Los Angeles to Chicago, reaction to Houston's death has been shock and sadness. The news seemed unreal to so many fans and even colleagues -- including Chicago's JenniferHudson, who sang a tribute to Houston at Sunday night's Grammy Awards..
On CNN Friday, Hudson recalled how influential Whitney Houston had been.
"As a kid, 11, I was sitting and creating duets between Whitney and I with her, "I Will Always Love You," the singer and actress said.
In 2009, Houston presented Hudson with a Grammy award.
"I've asked for Jennifer Hudson to come," said Grammy Awards Executive Producer Ken Ehrlich. "We're really, at this moment, talking about what it is she is going to do, but it will be something respectful. It's not going to be a full blown tribute."
Houston's former publicist Regina Daniel now lives in Chicago but traveled to L.A. for a pre-Grammy event. Regina's husband, George Daniels, says he saw Houston Thursday night at a concert where she made a surprise on-stage appearance.
The Daniels talked to ABC7 via telephone about this loss.
"A surprise guest shows up, and it was Whitney. Everyone cheered. She looked fine. I mean, this is a total shock," George Daniels said.
"I was really looking forward to seeing her this evening at the Clive Davis pre-Grammy event, but that is not to be," said Regina Daniels.
Some fans in Chicago were stunned when the news hit.
Much of that reaction came from churches. The church is where Houston honed her enormous singing talent.
At the Progressive Baptist Church, many thoughts were with the pop star.
"I grew up listening to Whitney Houston," said Quentin Washington, a cousin of the singer Jennifer Hudson. " 'The Greatest Love of All' is one of the first songs I learned to sing and play for myself as a kid."
Father Michael Pfleger of St. Sabina Catholic Church reminded parishioners of some of the pitfalls in Houston's career.
"Don't get tricked into getting attached to stuff that can take you out of here," Pfleger said. "I celebrate her. I love Whitney Houston."
Fans of her music were saddened.
"Well, I think it's really sad. I mean, she's such a beautiful woman and was so talented, and it's just sad that she passed away and had troubles in her life," fan Denise Maple said.
"I'm devastated. She's a multi-faceted legend in the music game. It's horrible," said Joe Starnes, also a fan.
"Tears immediately came to my eyes," said Goddess Bembry.
"It's saddening," said Ralph Murphy. "She was such a big influence on me as well as everyone in the industry."
"It's hard the even wrap my mind around the fact that she is gone," said Kristen Weber, who sang with the Soul Children of Chicago choir with Houston on the Oprah Winfrey show in 1998. "She was such an idol and icon."
V103 radio personality Herb Kent devoted part of his show Sunday to Houston.
"I just think she was a marvelous singer," Kent said. "As an R & B singer, she was phenomenal."
The cause of Houston's death has not been determined.
"Whitney was an angel," said entertainment blogger Art Sims."She reached the masses."