Mike rose to fame on 2017's Love Island, where he landed the nickname "Muggy Mike", before going on to make magazine headlines for his relationship with The Only Way Is Essex's Megan McKenna.
Mike also focussed on his career as a professional footballer. "My thoughts go out to all of Mikes friends and family".
"Mike you are going to be sorely sorely missed".
Mike Thalassitis, a soccer player-turned-reality star after appearing on the United Kingdom version of Love Island, was found dead Friday. My heart and soul and love goes out to his friends & family. "A lovely bloke gone far too soon".
"I can honestly say, Mike was thoughtful, caring and so fiercely loyal to his friends and family and really would do anything for them".
He dated The Only Way Is Essex star Megan McKenna before splitting up past year, and had appeared on the series Celebs Go Dating in 2018.
Mike's fans and his fellow Love Island stars have quickly taken to Twitter to pay tribute.
"I am absolutely in shock of the news". You were the kindest soul, you were so amusing and you had so much to live for.
A spokesman for ITV, which produces Love Island, said: "Everyone at ITV2 and Love Island are shocked and saddened by this awful news. I'm in complete shock", Olvia Buckland, another co-star, tweeted.
The reality star, who was also a star on E4's Celebs Go Dating, was due to be opening his own shop next week.
"I'm shocked and extremely saddened to hear reports of the passing of [Mike Thalassitis]".
"Our sincerest condolences go to his family & friends".
My heart goes out to his family and friends at this hard time.
When he signed up for Love Island, he was still part of the team at Margate FC.