Melissa Gilbert joins Hallmark's series "When Calls the Heart" in Season 12.

Melissa Gilbert will guest star in Season 12 of Hallmark's popular series "When Calls the Heart." Known for her role in "Little House on the Prairie," Gilbert's addition to the cast is highly anticipated by fans of the show, which follows the lives of residents in a small Canadian town during the early 1900s. The new season is set to continue exploring themes of love and community.