Michelle Dockery and Hugh Bonneville star in the new movie "Downton Abbey: The Grand Finale."

After 15 years, Downton Abbey is closing its doors.

The British TV phenomenon-turned-cozy film trilogy is drawing the curtains with one last movie, "Downton Abbey: The Grand Finale" (in theaters Sept. 12), which finds Lady Mary Talbot (Michelle Dockery) grappling with the ripple effects of divorce in 1930s high society.

The new film concludes the sprawling saga of the Crawley family, chronicled over six seasons of the ITV and PBS series "Downton Abbey." Created by Julian Fellowes (HBO's "The Gilded Age"), the show was an immediate sensation when it arrived stateside in early 2011, earning 15 Emmy awards and 69 nominations, as well as three Screen Actors Guild trophies for best ensemble, led by the late Maggie Smith as the formidable Dowager Countess Violet Crawley.

But the drama's rapid success wasn't without stress. In its heyday, the series was forced to contend with photographers trespassing on the set, hiding in bushes and trees in hopes of capturing major spoilers. As a result, the production would release misleading photographs and fake leaks to throw viewers off the scent of key plot points and cast changes.

“It did certainly feel overwhelming,” says Hugh Bonneville, who plays Mary's father, Lord Grantham. “And it also makes me wonder what it is about journalism that wants to spoil something people love before it comes out. The entertaining thing was to see the wrong speculation by supposed journalists, whose main role in life is to destroy something that’s celebrated. That was very strange to experience for the first time.”

At the same time, the cast “rallied around each other as the snowball grew of its reception around the world,” Bonneville says. The series found success everywhere from China to South Africa, and “there was something about the show that touched people wherever they were.”

“It’s just the humanity of the stories and the fictional world that Julian Fellowes created, where people were trying to get along in whatever way they could,” he says. “So the press attention, on the whole, didn’t feel intrusive or unkind – it was actually celebratory.”

Dockery similarly remembers the initial intensity of living under a microscope. The actress recently made headlines after debuting her baby bump on the "Downton Abbey" red carpet on Sept. 3 in London, although she coyly says she has "not yet" received any parenting tips from her costars.

Sudden fame "was definitely an adjustment – that’s the word I always come back to,” Dockery says. “When (the show) hit America, a lot of that feeling of not being anonymous, it was different. But we always felt like we were doing it together. We’re such a big family.”

It made it “easier,” she adds, being part of a large cast, all of whom were experiencing similar things.

“The times we're recognized the most is when we're all together,” Dockery says. “When people see five cast members all having a meal, we can't really get away with it.”

Simon Curtis directed two of the three "Downton" movies and is married to cast member Elizabeth McGovern, who has long portrayed Mary's mother, Cora. He remembers coming to New York with her to promote the series.

"We went with a group of actors from the show to see Dan Stevens, who was appearing on Broadway (in 'The Heiress')," Curtis says. "The play couldn't start because the audience was so excited to see the 'Downton' ensemble in the auditorium. And I thought, 'This is unusual. This is special.'"

This article originally appeared on USA TODAY: 'Downton Abbey' cast looks back on 'intrusive' paparazzi, overnight success

Reporting by Patrick Ryan, USA TODAY / USA TODAY

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