An old flame rocks Mitch Keller's world during Tulsa King season 3 - but he's still faithful to Dwight Manfredi above all else. Garrett Hedlund told Us Weekly exclusively ahead of the third season premiere on Sunday, September 21, that it's "wonderful" audiences get to see his character "be smitten" by a "beautiful blast from the past" in the form of newcomer Bella Heathcote's character, Cleo. She is "that gal that he just can't let go of, that he can't quit, that hurts so good," Hedlund, 41, teased to Us. "You get to see them re-embark on that journey.