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On a night during which the late Whitney Houston was honored and the news of Donna Summer's death was still fresh on everyone's mind, the music industry was hit with another unfortunate passing of Bee Gees' Robin Gibb. The stars at the Billboard Music Awards reacted to the sad news.

PICS: Remembering Robin Gibb: A Life in Pics

"Robin was such a sweetheart. He was always giving," said Motown artist Gladys Knight. "[He was] very talented and...family-oriented."

Robin Thicke, who was an award presenter on the night, revealed a personal tie with Mr. Gibb. He revealed to ET that his father is a longtime friend of the Gibb family and some of the Gibbs to attend his father's wedding, where they were "the life of the party." "I'm a huge Bee Gees fan and my heart and soul goes out to the family," he said. "Today is a day to celebrate their music and their legacy."

VIDEO: ET's Last Interview with Robin Gibb

Lisa Marie Presley, who lost her father Elvis Presley at age 42, gave her opinion on honoring late musicians. "I think that people should be a little more honored before they go," she said. "It's incredible once they're gone to [tribute them] but a lot of times they don't know. It gets to a point where we don't always give them what they need...It's sad that it has to happen afterwards."

Stevie Wonder put the latest string of departed musical talents into a greater perspective. "We lose people everyday. The thing about losing singers [is that] we have their voices, we have their talent and [their legacy] is going to last beyond our lifetime," he said.

VIDEO: ET Flashback: Bee Gees Reunion

Check out the video above for more reactions on the passing of Robin Gibb and Donna Summer as well.