The singer had previously described himself as bisexual but insisted that he wanted his private life to remain private.
Mika has since told Instinct Magazine: "If you ask me, 'Am I gay?', I say yeah. Are these songs about my relationship with a man? I say yeah.
"And it's only through my music that I've found the strength to come to terms with my sexuality beyond the context of just my lyrics. This is my real life."
Back in 2010, Mika said: "Look, I've always said I can fall in love with a man. I can fall in love with a woman. And I've always said that I have no shame in that. And I don't think there was any negative reaction to what I said coming out as bisexual."
Mika releases new record The Origin of Love on September 16.
Listen to Mika's single 'Celebrate' below: