The 78-year-old actor, who is an advocate of LGBTQ rights, took to Twitter and said coming to terms with one's sexuality helps one lead an honest life.
"I've never met a gay person who regretted coming out
including myself. Life at last begins to make sense, when you are open and honest.
"Today is the 30th anniversary of the BBC radio discussion when I publicly said I was gay. So I'm celebrating!" McKellen wrote.
"The Lord of The Rings" star had made his sexual orientation known to fellow actors early on in his stage career.