Speaking at the Edinburgh TV Festival, Hart described her sitcom as "universal".
"I don't think about being middle-class or writing a middle-class sitcom," she said. "I really shy away from labels in comedy. Funny is funny. It's irrelevant really.
"If you wrote a middle-class sitcom, the problems would be a broken Land Rover or buying a new watch... my problems in Miranda are universal. It's classless."
Hart confessed that she did have concerns about the show's move to BBC One, claiming that "two or three million more viewers are expected".
On the subject of the show's breakout success, she added: "I can't believe it, I'm still in shock. I knew we'd do excellent with the WI, but I really didn't think the broad demographic would.
"I knew the industry wouldn't because studio shows get slammed."
She also played down stories about her wanting to star in Doctor Who, adding: "Everyone wants to be in Doctor Who. We all want to be in Downton Abbey and Doctor Who. We all do."
> Miranda Hart Masterclass - Live Blog