Dan Stevens as Matthew Crawley and Michelle Dockery as Lady Mary Crawley. (Nick Briggs/AP)

Nearly 8 million people caught Sunday’s third season debut of “Downton Abbey” on PBS — the crunchy-gravel drama’s biggest audience ever, according to early stats.

The third-season opener nearly doubled the 4 million who’d watched PBS’s unveiling of the second-season debut. Sunday’s opening number also is quadruple PBS’s average primetime performance.

Overall, that second season wound up the most watched series in the “Masterpiece” franchise’s history. So far, this season seems bound to eclipse that and set a new “Masterpiece” record.

From 9-11 p.m. Sunday, PBS was the second most watched broadcast network, behind only CBS with its original episodes of “The Good Wife” and “The Mentalist,” according to early, metered-market numbers.

According to those early stats, 11 percent of homes in Washington, in which TVs were turned on Sunday night between 9-11 p.m., were watching “Downton.”

“I’m thrilled to see so many viewers return to the Crawley family’s delicious drama and intrigue,” “Masterpiece” exec producer Rebecca Eaton said Monday.

“Downton” first hit PBS on January 9, 2011. This season rejoins the story as World War I is over, the engagement of Lady Mary and Matthew is on. And Shirley MacLaine has joined the cast, to chew some scenery, pitted against Maggie Smith. Our money’s on Maggie.