In June this year, a CNBC co-anchor Simon Hobbs had inadvertently revealed the sexual orientation of 53-year-old Cook, during a live show, "Squawk on the Street".
Hobbs had reportedly said, "I think Tim Cook is fairly open about the fact that he's gay at the head of Apple, isn't he?"
Till now, Cook had never openly revealed his sexual orientation, but he has always been seen as a strong advocate for the LGBT (Lesbian, Gays, Bisexual and Transgender) rights.
For the first time, Cook has written about his sexuality and has officially come out as a gay and described his sexuality as "among the greatest gifts God has given him."
In an opinion article for Bloomberg Business Week, Cook has written, "For years, I've been open with many people about my sexual orientation. Plenty of colleagues at Apple know I'm gay, and it doesn't seem to make a difference in the way they treat me."
"While I have never denied my sexuality, I haven't publicly acknowledged it either, until now. So let me be clear: I'm proud to be gay, and I consider being gay among the greatest gifts God has given me", he has written.
"Being gay has given me a deeper understanding of what it means to be in the minority and provided a window into the challenges that people in other minority groups deal with every day. It's made me more empathetic, which has led to a richer life. It's been tough and uncomfortable at times, but it has given me the confidence to be myself, to follow my own path, and to rise above adversity and bigotry", he has written.
"There are many places where landlords can evict tenants for being gay, or where we can be barred from visiting sick partners and sharing in their legacies. Countless people, particularly kids, face fear and abuse every day because of their sexual orientation", he goes on to write.
"I don't consider myself an activist, but I realize how much I've benefited from the sacrifice of others. So if hearing that the CEO of Apple is gay can help someone struggling to come to terms with who he or she is, or bring comfort to anyone who feels alone, or inspire people to insist on their equality, then it's worth the trade-off with my own privacy."
"Part of social progress is understanding that a person is not defined only by one's sexuality, race, or gender", he further wrote.
Cook took over as the Apple CEO in August 2011 shortly before founder Steve Jobs passed away, after battling against pancreatic cancer.