Wham! was wildly successful in the early 1980s, producing mega hits like "Wake Me Up Before You Go-Go!" and "Last Christmas." The duo broke up after Michael's breakout solo hit, "Careless Whisper," led him to pursue a career on his own. Despite going their separate ways musically, the pair remained close friends.
In addition to Ridgeley, a number of well-known British singers have taken to social media since the tragic news broke.
Elton John shared a photo with Michael from a charity performance in 2011 for the Elton John AIDS Foundation at London's Royal Opera house, captioning it, "I am in deep shock. I have lost a beloved friend - the kindest, most generous soul and a brilliant artist. My heart goes out to his family, friends and all of his fans."
Robbie Williams -- who like Michael was in a successful group, Take That, before breaking out solo and having a very successful career overseas -- was also a friend of the late singer and tweeted, "Oh God no …I love you George …Rest In Peace." Last year, Williams performed an a capella version of "Freedom" and sang happy birthday to Michael while on stage in Bucharest, Romania.
Spice Girl singer Geri Halliwell also paid her respects, sharing a photo of her and Michael alongside a note reading, "So so sad, R.I.P George, a dear friend, the kindest, most generous & talented person. My thoughts are with his family."
According to reports, Michael died on Christmas. His rep told ET, "It is with great sadness that we can confirm our beloved son, brother and friend George passed away peacefully at home over the Christmas period. The family would ask that their privacy be respected at this difficult and emotional time. There will be no further comment at this stage."
In a statement, the Thames Valley Police said, "Thames Valley Police were called to a property in Goring-on-Thames shortly before 2pm Christmas Day. Sadly, a 53-year-old man was confirmed deceased at the scene. At this stage the death is being treated as unexplained but not suspicious. A post mortem will be undertaken in due course. There will be no further updates from Thames Valley Police until the post mortem has taken place."