(CNN) -- On Saturday, "Doctor Who" celebrates its historic 50th anniversary with a simulcast special in 75 countries. But it almost wasn't to be.
In 1989, the show was canceled. A 1996 attempt to reboot it lasted as long as one TV movie. Finally, in 2005, the show was revived, and its fanbase has grown ever since.
News of the 12th Doctor, Peter Capaldi, made worldwide headlines. Fans of the Doctor -- an alien "Time Lord" who travels across space and time -- are no longer relegated to fan sites and "Doctor Who" conventions.
The show is now a high point of each year's San Diego Comic-Con and prominently referenced on shows like "The Big Bang Theory" and "Community." It's also the No. 1 rated show on BBC America and won a prestigious Peabody Award this year.
That's quite an achievement for a show aimed at children that was quietly launched on November 23, 1963.
Marcus Wilson, a producer "Doctor Who" since 2011, spoke to CNN about the show's legacy and what fans can expect for the big 50th anniversary episode, "The Day of the Doctor."
CNN: What do you think it is that has helped the show last 50 years, continuing to grow its fan base?
Marcus Wilson: It's a very simple premise, yet it has endless flexibility: A man travels through time and space, fighting for good against evil wherever he goes. It's accessible, uplifting and endlessly entertaining because it engages the viewer's imagination and credits them with intelligence. It can regenerate itself (even its leading man) to keep the show modern and in tune with its audience.
CNN: What sets the fandom for "Doctor Who" apart from others?
Wilson: "Doctor Who" fans are the best in the world. They've stayed with the show through thick and thin. They are devoted, smart and not afraid to let us know how they feel! They feel a part of the show, particularly as they kept it alive through all the years it was off air. We're very lucky to have them behind the show.
CNN: How has the fandom evolved over the years?
Wilson: It's a generational thing. Parents who watched the show as kids are now sharing it with their kids. The audience is constantly renewing. The late teenage/early 20s audience seems to be growing as the classic show is being rediscovered on iTunes and box sets, and the brand spreads from the UK across the world.
CNN: How important do you think the "new" series has been in attracting fans?
Wilson: New material always rewards devotion, but we've tried to develop the show and aspire to new ways of telling stories to keep the show evolving. The show changes to keep pace with the modern world. It's very accessible, deliberately so, so hopefully the great stories, higher production values and superb cast have attracted people who had maybe dismissed the classic series.
CNN: What are your fondest memories of "Doctor Who"?
Wilson: As a fan, sitting down on a wintry Saturday night with crumpets to watch Tom Baker's Doctor. As a producer, standing in Central Park shooting, surrounded by a horde of fans. It was quite exciting and humbling at the same time.
CNN: Is there anything in particular that you can promise fans when they see the 50th episode? Any teases of what can they expect?
Wilson: It's both a celebration of the past 50 years of "Doctor Who," and the foundations of the future of the show. The next chapter starts here. It's both a reward for the long-term fan -- questions will be answered! -- and the perfect place for a new viewer to jump on. A tease? A picture is worth a thousand words. ...
CNN: What do you think is the show's greatest contribution to science fiction? To television?
Wilson: I think we've proved you can't keep a good show down!