Theo James has faced a lot of acting challenges over the course of his career, but nothing comes close to what he had to contend with once Naomi Watts was cast as his mother in "Insurgent," the follow-up to "Divergent." And it's not just their 16-year age difference. 

"Firstly — which is interesting because she's playing my mum — she's a bit of a babe. I had to get past that," James admits. "But no, she's really interesting in this film because she has a very different energy. She's very calculating, but at the same time she has a warmth and a kind of gentleness that almost juxtaposes what her real ambition is. It was kind of nice, that, in a way because it puts you on the back foot not only as the audience but as the character when you're doing the scenes with her. She's not staring you down in a kind of abrasive way. It's very loving and sweet but intense at the same time."

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That estranged mother-son relationship echoes the troubled father-son relationship he played in the first film opposite Ray Stevenson. And James had absolutely zero life experience upon which to draw for either pairing.

"He has a not great relationship with either of his parents, and luckily I have two good parents," he says. "That was one thing that was something that needed a little addressing when it came to the Naomi scenes. It is kind of the same, i.e., he's estranged from both parents. But I didn't want it to be a repeat of the same beat he's already had with his father, so we discussed that. But in terms of drawing on my own family, I think the importance of family is a big thing from me, so yeah, using those feelings and thoughts and philosophy and incorporating that into the character is definitely something that I did … a little."

Much easier to deal with was stepping back into the role of Four for the second installment of the successful YA franchise. "You know, second movie around you've already set up some of the key storyline elements, so we have that luxury of jumping straight into the action without exploring characters and introducing them again," James explains.

That also meant jumping back into his onscreen relationship with Shailene Woodley, as series star Tris. And that's a relationship James insists he has no trouble exploring.

"I like the fact that they have mutual respect for one another," he says. "I think the relationship is different in this film in the sense that they have a mutual respect for one another. Her femininity doesn't detract form her masculinity, and the other way round. She's a very strong female lead character, but she is also very feminine at the same time."

Follow Ned Ehrbar on Twitter: @nedrick