On Twitter, Fawaz shared a link to the music video for Michael's song, "This Kind of Love," with the caption: "My Baby."
He later posted a pic to Instagram of himself with the pop legend, along with a heartfelt message. "I will never stop missing you, George," Fawaz -- whose account is not verified but is followed by Michael -- wrote. "The kind and the most beautiful man ever. Xxx."
PHOTOS: A look at the happy couple together
According to Michael's rep, the GRAMMY winner died of heart failure, though the official cause of death has yet to be confirmed. Earlier this week, Fawaz tweeted that he was the one who discovered the 53-year-old musician's body.
"It's a X-mas. I will never forget finding your partner dead peacefully in bed first thing in the morning," he wrote. "I will never stop missing you xx."
Fawaz also told The Daily Telegraph that he and Michael had made plans to spend time with one another on Christmas Day. "We were supposed to be going for Christmas lunch. I went around there to wake him up and he was just gone, lying peacefully in bed," he recalled. "Now everything is ruined. I want people to remember him the way he was. He was a beautiful person."
The two had kept a low profile about their relationship. They had not been photographed together since September 2015 in Zurich, Switzerland.