It's going to be a season of changes for the characters on the family drama Heartland, according to the show's head writer and executive producer, Heather Conkie.

"People are changing, relationships are evolving," she explained. "It's really exciting. We keep trying to do better and better, and I think we are."

Among the differences viewers will notice during Heartland's third season, which kicks off Sunday on CBC, is a full-blown romance between the show's attractive young lead characters Amy Fleming (Amber Marshall) and Ty Borden (Graham Wardle).

"People spent the whole second season waiting for Amy and Ty to get together on the romantic front," Conkie said. "And this year they are a couple, but that doesn't mean they don't have their ups and downs."

Sunday's season opener has Amy dealing with something even more stressful than teenage affairs of the heart. After she is caught on camera rescuing a trapped horse, Amy becomes an Internet sensation and is thrust uncomfortably into the spotlight.

While Amy and Ty struggle to deal with her sudden fame, the actors themselves are enjoying the celebrity treatment.

"Everyone I meet, they are so ecstatic about the show," said Marshall, a London, Ont., native who now spends much of the year in Alberta, where the series is shot.

"I was just buying sushi the other day and this girl who was taking my order was like, 'I have to ask, you're Amy right? I just absolutely love that show.'

"It's nice to hear that feedback."