The Downton Abbey star was still mourning the loss of her beau John Dineen to cancer when she started filming U.S. drama Good Behavior earlier this year (16), and her determination to press on with her work really impressed co-star Juan Diego Botto, who plays her con artist character Letty Raines' love interest.

"She's amazing," he told reporters at the show's New York City premiere on Monday night (14Nov16). "She's the kind of actor if you had to choose just one kind of actor to work with for the rest of your life, that would be the kind of actor she is and she's very passionate about what she does."

Good Behavior is based on the book of the same name by Blake Crouch, and the author, who co-produced the TV series, admired her willingness to channel her own dark experiences for the role, reports

"It was, like, the best experience in television that I've had, working with Michelle, because she was so fearless going into this role," he explained, adding, "I mean, the character of Letty Raines is this broken, damaged, resilient character, and Michelle was game to just go there and to go to these incredibly dark places and she brought out things in this character that I didn't even know were there."

As for Michelle, she was grateful to be given the chance to try something so drastically different from her role as Lady Mary Crawley in hit period drama Downton Abbey.

"(Letty Raines is) an amazing character to play," she said. "I was thrilled they had faith in me to do it."

Good Behavior premiered in the U.S. on Tuesday (15Nov16).