He found fame on the 2017 series of the show and was a semi-professional footballer.
Several reality TV stars posted tributes to Thalassitis after news of his death was reported.
Fellow Love Island contestant Chris Hughes tweeted: “His name wasn’t Muggy Mike. Please stop brandishing that. His name was Mike Thalassitis, and every inch of my heart goes out to his family & friends. A good guy, taken far, far to soon.”
The Only Way Is Essex star Ferne McCann posted: “So so so so sad. Mike you absolute gent. I have no words. My heart and soul and love goes out to his friends & family. Too young. RIP.”
Alex Bowen and Rachel Fenton, who both also appeared on Love Island, tweeted their respects.
Fenton tweeted: “I’m lost for words. My heart breaks for your family RIP @MikeThalassitis.”
And Bowen wrote: “I cant get my head round this RIP brother.”
Stevenage FC, for whom Thalassitis began his football career, tweeted: “Everybody at #StevenageFC is shocked & saddened to hear the tragic news about former player Michael Thalassitis.
“Our sincerest condolences go to his family & friends.