It's hard to imagine a time when Sir Ian McKellen was still in the closet.

Some may know the celebrated 78-year-old actor best as Gandalf in the Lord of the Rings films and Magneto in the X-Men franchise, but he's also an outspoken activist who has played an integral part in advancing LGBT rights in the U.K. and abroad.

At 48, although he had yet to discuss his sexuality with his family, McKellen came out as gay during a BBC radio interview on January 27, 1988, to criticize Section 28, a British law prohibiting the "promotion of homosexuality."

This marked the first of McKellen's many actions as a vocal LGBT rights advocate; the following year he became a founding member of the activist organization Stonewall, which campaigns for gay equality.
 Section 28 was finally repealed in 2000.

"I’ve never met a gay person who regretted coming out—including myself," McKellen tweeted Saturday. "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 publically said I was gay. So I’m celebrating!"

During a 2015 interview with Charlie Rose, McKellen recalled that it was “just the right time” for him to declare his sexuality to the world. “A law was being passed I didn’t approve of which disadvantaged gay people, and that’s when I came out," he said. “I wish I’d felt able to come out earlier.”

Seen in last year's live-action Beauty and the Beast, McKellen is also the subject of a new documentary, McKellen: Playing the Part. While promoting the doc, he recently noted that he'd like to be remembered more for his activism than his acting.

“I’m very proud of my small contributions to changing the law in this country and changing attitudes, all for the better,” he said. “And I suppose in the scheme of things that is more important and the more merit and longer lasting than any acting that I have done.”

McKellen has shared his opinion that gay people are “disregarded” by the film industry, comparing the struggle of gay actors to that of both female actors and actors of color. However, he still urges gay Hollywood actors to come out.

“A closet’s a really nasty place to live, you know?" McKellen told the Hollywood Reporter. "It’s dirty, it’s dusty, it’s full of skeletons. You don’t want it. Open that door—fling it wide and be yourself.”