“Did you expect it to turn into all of this?,” Oprah Winfrey asked Ellen DeGeneres on an episode of her talk show that aired on the afternoon of April 30, 1997. Two weeks earlier, a Time cover had debuted, featuring DeGeneres and the instantly famous words “Yep, I’m Gay.” On April 25, DeGeneres spoke to Diane Sawyer on 20/20 and said, “I decided this was not going to be something that I was going to live the rest of my life being ashamed of.”

Hours after the Oprah interview aired, DeGeneres’s charismatic bookstore owner character, Ellen Morgan, followed suit, coming out as gay in a one-hour, two-part episode of her sitcom Ellen. “The Puppy Episode” was watched by an estimated 44 million people, nearly three times the show’s usual ratings.

It’s been 20 years since that April. DeGeneres has hosted her own daytime talk show, also called Ellen, for nearly 14 years. She’s hosted the Oscars, won the Presidential Medal of Freedom, starred in two blockbuster cartoons, and all the while lived openly as a gay woman.

“I mean, I knew that it would be big, but I had no idea that it would be this big,” DeGeneres replied to Oprah in that 1997 interview. Twenty years later, it’s difficult to comprehend just how big it really was.

In May of 1996, DeGeneres invited staff members of the show to her home for what Dava Savel, who served as an executive producer that year, recalled on a phone call with Vanity Fair as “a meet-and-greet.” DeGeneres, though out to her writing staff and many other people in her life, would be publicly coming out of the closet for the first time. And she wanted Ellen Morgan, then in her third season of the ABC sitcom, to come out, too.

As DeGeneres would tell Oprah she had always felt it wasn’t anyone’s business to know whom she was dating. But hiding became hard: “Then I realized that as long as I had this secret that I worried about all the time that it made it look like something was wrong.”

The writers built it up slowly. They inserted little jokes throughout the entire fourth season to tease out the character’s eventual coming out. “Are you coming out?,” Ellen Morgan’s friends would call, before she’d leap out of a door. “I was in the closet,” she playfully shouted as she exited a coat closet in one scene.

Mark Driscoll, who was also an executive producer on the fourth season, said that he remembers the excitement on the staff as the season began to inch toward an episode that hoped to break new ground on a hot-button social issue. “Ellen was so loved by audiences; she was so much the girl next door and so sweet. She was the perfect person to dispel people’s fears about what a gay woman might be like.”

Before Ellen Morgan became the first gay lead character on television, L.G.B.T.Q. characters were often tragic—think Tom Hanks’s Oscar-winning performance in Philadelphia—or, more often, nonexistent. With so few celebrities out of the closet, those who were open faced discrimination. And real-life discrimination was just as real. As Danish-British comedian Sandi Toksvig revealed in 2014 , she was fired from a 1994 charity event because, according to Toksvig, the organizers didn’t want Princess Anne, in attendance, “to meet a lesbian.”

On March 14, 1997, “The Puppy Episode” taped at its L.A. Disney-ABC lot. The title was a red herring to prevent leaks, but came with its own meaning. As DeGeneres explained on an anniversary episode of her talk show, which airs Friday, “The writers told the executives that they wanted me to come out, because my character needed to be in a relationship after four years of not being in a relationship. Someone at the studio said, ‘Well, get her a puppy; she’s not coming out.’ ” In the end, Savel noted, studio executives eventually came on board with the episode, and worked to keep it a surprise. All scripts were printed on dark burgundy paper that could not be Xeroxed. At the end of the day, everyone had to turn in their scripts to be kept under network lock and key.