Deon Estus, known best for playing bass for 1980s pop band Wham!, has died. He was 65.

"It is with real sadness I post that Deon Estus passed away This Morning," read a post from the musician's Twitter account on Monday. "Deon was mostly known as the third member of Wham!"

The post continued: "Deon was passionate about music and loved interacting with his loyal fans."

No cause of death was provided. A source told Fox News that he died of heart complications, and clarified that he died on Sunday as opposed to Monday, as the tweet suggested.

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Estus' partner Brenda Kaye Pierce also shared a message of mourning on Facebook on Monday.

"My dearest, closest partner and significant other of 4 years transitioned and all I can remember is our last conversation the day before," she wrote. "My heart will need time to heal. R.I.P. Deon. Love you forever."

Wham! was primarily comprised of singers George Michael, who passed away in 2016, and Andrew Ridgeley.

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Ridgeley, 58, posted on Twitter after the news broke.

Deon Estus, singer and Wham! bassist, has died at the age of 65. (Photo by Michael Putland/Getty Images)

"[Very] sad news today of Deon Estus’ death. A lavishly gifted bass guitarist, a charismatic & impish character & a rock of the WHAM! rhythm section," he said. "He lives large in the memory, he radiated warmth, humour & life’s illuminating light, my heartfelt commiserations go out to his family."

Estus had a hit of his own, "Heaven Help Me," which landed in the top five on the Billboard Hot 100 in April 1989, per the outlet. Michael produced, co-wrote and provided backup vocals for the track.

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Estus' only solo album came in the form of "Spell" in 1989 and featured "Heaven Help Me" as well as the title track and "Me Or The Rumors."

Wham!, on the other hand, was known for pop hits like "Wake Me Up Before You Go-Go," "Last Christmas" and "Everything She Wants."

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Billboard reports that he worked with several other music legends like Tina Turner, Elton John, Marvin Gaye, Frank Zappa and Annie Lennox.

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