At a holiday party, a colleague asked if I watch “Downton Abbey,” the British series about an early 20th-century earl, his American wife, their three daughters and their ginormous house. I told the truth: No. She accused me of being a reverse snob: i.e., I’m glued to trash TV yet I avoid sophisticated fare.

To make amends, I previewed the Season 3 opener, which airs Sunday at 9 p.m. on PBS.

Among the plot points: A valet killed his wife … or did he? A daughter is wed to … OMG … the chauffeur! Dad is out to quash the romance between awkward offspring Edith and an older gent with a lame arm. All the while, Maggie Smith, as the earl’s acerbic mum, zings zingers faster than any Bravo real housewife. Smith on her daughter-in-law’s mother: “When I’m with her I’m reminded of the virtues of the English.” A bystander: “But isn’t she American?” Smith: “Exactly!”

So really, “Downton Abbey” is just like trash TV (and just as addictive), only the characters dress better and talk real fancy. But … spoiler alert … the show’s highbrow sheen could crack. In Season 3, the earl loses his shirt — both literally and figuratively.