The brilliance of the long-running sci-fi series Doctor Who is built right into its central concept. By its very nature, it can go anywhere and anywhen. Wanna do a story set in the Ming Dynasty? No problem. How about a visit to the first human colony on Mars? Easy. Or hey, what do you say things go even further, all the way to the day the sun burns out and the Earth dies? No sweat.

All that storytelling flexibility also means the show can encounter virtually any kind of sentient life its showrunners can dream up, which makes it a vehicle not just for all manner of cool-looking aliens, but also all manner of diverse human characters. Now, that flexibility has led to the latest (some would say long overdue) in a series of increasingly progressive character introductions: The show’s first openly gay Companion.

Back up a second for a newbie-friendly further explanation of the concept: Doctor Who is about the adventures of The Doctor, a time-traveling alien who can regenerate into a new form in order to prevent death, allowing many different actors to portray him (at the moment it’s Scotsman Peter Capaldi) in the years since his 1963 debut. To ease the loneliness of his travels, he usually has a friend with him, known to fans as The Companion, who’s usually human to provide a little extra audience identification. The new Companion, who will be introduced in the new season premiere on April 15, is Bill Potts (Pearl Mackie), a mixed-race Brit who will also be immediately out of the closet for viewers.

“It shouldn’t be a big deal in the 21st Century. It’s about time isn’t it?” Mackie said. “That representation is important, especially on a mainstream show.

"I remember watching TV as a young mixed race girl not seeing many people who looked like me, so I think being able to visually recognise yourself on screen is important.

”[Being gay] is not the main thing that defines her character - it’s something that’s part of her and something that she’s very happy and very comfortable with.“

Bill is far from the first openly gay character on the show, but she is the first whose name will be right there next to the star’s in the show’s credits, marking a major representation victory for Who’s particularly diverse fanbase.

Of course, one key hurdle on the diversit front remains for Who fans: The Doctor is canonically able to change his appearance in a number of ways upon regeneration, including switching race and even gender. That fact has led to a wave of fan demand, particularly in the last five years or so, for an actor of color or a woman to have a chance to play the role. Given that this season will be Capaldi’s last, those demands will likely up their intensity yet again in the buildup to casting his replacement later this year, but even as fans hope for a change, they’ve also come to expect disappointment. Bill’s sexual orientation will likely be held up as an example of the show doing right by the fans, and it is, but this is not the end of the quest for more Doctor Who diversity. For the moment, though, it’ll do.