Credit: Robert Viglasky/Hartswood Films for MASTERPIECE

The world’s biggest premiere date mystery has been solved. EW has exclusively learned the return date for Sherlock, along with some details about how the third season roll-out plan came together.

Sherlock will return to PBS Masterpiece on Jan. 19 at 10 p.m. That means the show will air back-to-back for the first time with that other hugely popular and influential Brit import, Downton Abbey (which returns Jan. 5).

This announcement caps nearly two years of rabid fan speculation about when the third season of the international sensation will premiere. This also marks first time the mystery-thriller’s U.S. air date has been announced before the BBC reveals its UK premiere date (the BBC has the “first window” rights to air the show, so UK fans can at least take heart in knowing they will almost certainly get season 3 sometime before Jan. 19).

Masterpiece executive producer Rebecca Eaton tells EW that this is the best season yet of Sherlock, which stars Benedict Cumberbatch as the legendary detective and Martin Freeman as his partner Dr. Watson (the first official image of the actors from season 3 is above). “They’re fantastic,” she says of the new episodes. “They are jaw dropping. They are like small movies. Benedict and Martin are so in their Sherlock-Watson groove. They are so comfortable with that relationship it’s like being in the room with them.”

Sherlock executive producer Sue Vertue added in a statement: “We are hugely excited about this next series of Sherlock, and have worked closely with our partners, Masterpiece and PBS, to bring these episodes to U.S. audiences in January. We promise our fans that Season 3 is worth waiting for.”

Sunday entertainment programming on the Big 4 broadcast networks has been seriously weakening in the ratings this fall. So the British invasion power-pairing of hugely anticipated Downton season 4 and Sherlock season 3 could make PBS a significant player on that night in January. “We love that Sherlock fans are so passionate and eager to see Season 3,” said PBS chief programmer Beth Hoppe in a statement. “The pairing of Downton Abbey and Sherlock in January offers a blockbuster night of British drama only on PBS stations.”

As EW first reported, Sherlock season three production was delayed partly due to skyrocketing demand for its two stars, with Cumberbatch landing roles in Star Trek and several other films, while Freeman snagged the lead of Bilbo Baggins in Peter Jackson’s The Hobbit films (in which Cumberbatch also plays a small but pivotal role, as the voice of the dragon Smaug in December’s second film in the trilogy — which ought to make the climactic Bilbo-Smaug confrontation rather surreal for Sherlock fans). Sherlock season three production was then split into three chunks over the course of this year rather than being shot continuously like on most shows.

“The first holdup was the boys, of course, and getting all of them together — not just Benedict and Martin but also [creators] Steven Moffat and Mark Gatiss,” Eaton says. “They had to break up the production to accommodate all the movies they wanted to make.”

Once production wrapped in August, the BBC and PBS had to plan their respective schedules. Though fans may feel the wait has been endless, Eaton says that, if anything, the scheduling was hastened because of fan interest. “This is about as quickly as we could have possibly got them on the air once they were made,” Eaton says.

Since the BBC date is not yet public, one lingering question is how big of a gap there will be between the UK and U.S. air dates. Cumberbatch and U.S. fans have lobbied for the show to air in both countries on nearly the same date. Such a move would help prevent the stateside audience from getting spoiled on the show’s surprises (mainly: How exactly did Sherlock survive his rooftop plummet at the end of season two?). It’s an issue overseas audiences are all-too-accustomed to facing while waiting for American shows, and one that TV companies have been giving increasing consideration given the rise of online piracy. “There are things fans would like to do we just can’t do,” Eaton says. “But we do pay attention. This isn’t just the fans of Sherlock speaking up, it’s the nature of the shrinking TV world. So we try to manage that with all the intricacies involved. It’s all taken into consideration.”

Obviously we don’t yet know the BBC date. But given that the U.S. fans had to wait three months after the 2010 BBC premiere to see the first season of Sherlock, then had to wait four months for the 2012 second season after its UK debut, no matter when the BBC schedules its season three premiere, the gap is going to be less than before since Jan. 19 is less than three months from now (that sentence was totally convoluted but does make sense).

The first episode is called “The Empty Hearse” and solves the mystery of Sherlock’s death. The second episode is titled “The Sign of Three” and features — spoiler alert if you haven’t been following the online chatter about the new season — Watson getting married to Mary Morstan (played by his real-life partner, Mr. Selfridge actress Amanda Abbington). The third episode is “The Last Vow” and airs Feb. 2. And then the wait for new Sherlock will begin all over again. Season 4 is heavily presumed to be happening, but the BBC has not confirmed this and the company tends to wait until each season of Sherlock airs until announcing the next.

“I think there’s such an appetite for Sherlock because every season we do they’re bites; the season isn’t 13 episodes, which we would love,” Eaton notes. “They’re complicated to make and we can’t do more than that. So you never get quite enough even when you get a new season. Even more than with Downton, because Downton is 10 hours and it comes back regularly once a year. So Sherlock creates an unusual appetite.”

RELATED: If you haven’t seen Cumberbatch’s Comic-Con greeting about how Sherlock survived his fall, it’s a must-see here