Garrett Hedlund says viewers will learn more about Mitch's past as Bella Heathcote joins the cast of Tulsa King Season 3, premiering Sunday.

"There's a tenderness to a lot of these scenes that we hadn't gotten to see, at least not from Mitch, previously. It makes me smile."

Created by Taylor Sheridan, the show follows Dwight Manfredi (Sylvester Stallone), a New York gangster who moves to Oklahoma and assembles a crime family from the local talent, including Mitch, an ex-con bartender who goes on to become Dwight's right-hand man.

"The reason [Cleo's] back in town is interesting and it stirs an idea within me that I bring to Dwight, which then blossoms into being our whole next venture through all of Season 3. So, I have her to thank in more ways than one and I think audiences are really going to get sucked into this season."

"It shows a wonderful part of their dynamic," Hedlund said.

"They've been through some of the same ringers and don't want to repeat them. They want to proceed with danger wisely and for Dwight to trust Mitch right off the bat gives Mitch a great deal of respect."

"Everything made me want to [take the job.] Sly Stallone, Taylor Sheridan, just stepping into something that's so beloved and so much fun and just has this humor and tension and suspense," Heathcote said. "Sly and Tyler, they've just got the modest touch."

The actress didn't give much away regarding who Cleo is other than to call her "fun, tough, sassy and flirty."

"I feel like I'm describing a perfume," she laughed, noting there is a running joke on the show's set about how she is obsessed with how good Stallone's cologne smells.

"Inside scoop: Sylvester Stallone smells amazing!" Heathcote said. "I pointed that out one day. He was delighted. He didn't seem disturbed at all and then I really gave Garrett a complex, about how he smelled."

"It wasn't a complex," Hedlund clarified. "It was about my misconception that she was so enamored by how Sly smelled. I was like, 'Wow, for the last 20 years I've thought that ladies stopped enjoying cologne.'"

"He seemed like his whole day turned around," Hedlund said.

"So, then I was flying back to my son later that day and I see all the perfume ads and duty free [products] at the airport. I was like, 'I [expletive] want to be told I smell good,'" he joked. "That's the thing, guys. Just don't be too proud to smell good because the appreciators of it are not a dying breed."

Heathcote said the kind of banter she and Hedlund were demonstrating is how their characters behave in the show.

"There's just a lot of ribbing, a lot of needling," she said, noting a lot of it was improvised.

"There actually wasn't anything written for our characters," Hedlund quipped. "It just said, 'Cleo and Mitch drive,' and we figured it out."