The 26-year-old rose to fame when he appeared on the ITV show Love Island in 2017. His grandmother, whom Thalassitis was living with full-time to take care of, also died recently.
Chris Hughes, who was in the villa with Mike, tweeted: "His name was Mike Thalassitis, and every inch of my heart goes out to his family & friends". Mike, you were loved by all of the Love island family.
Love Island star Mike Thalassitis has died aged 26 years old near his home in Essex, according to reports. My heart and soul and love goes out to his friends & family. "A good guy, taken far, far to soon", he wrote on Twitter.
While Tyla Carr, who was coupled up with Mike during the show, said "I can't believe the call I've just had". You were the kindest soul, you were so amusing and you had so much to live for.
He dated The Only Way Is Essex star Megan McKenna before splitting up a year ago, and had appeared on the series Celebs Go Dating in 2018.
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The nickname "Muggy Mike" came about after he had an argument with fellow Love Islander Chris Hughes. I'm in shock. Mike you are going to be sorely sorely missed. Love and prayers to the family and friends of Mike Thalassitis. "I'm in complete shock", Olvia Buckland, another co-star, tweeted. He also appeared on Celebs Go Dating one year later in 2018.
"In absolute shock. Mike Thalassitis your lovely self and smile will be truly missed. Will never be forgotten", Love Island's Kady McDermott tweeted.
"Our thoughts and deepest condolences are with Mike's family and friends at this very sad time".
A Go Fund Me was set up to help with Mike's friend after his death.
When he signed up for Love Island, he was still part of the team at Margate FC.