One of the biggest looming mysteries on This Is Us: Why does Kevin (Justin Hartley) hate his stepfather Miguel (Jon Huertas) so much?

"The sheer idea of having your deceased father's best friend marry your mother is a little bit 'ehhhhh,'" Hartley tells us.

We may start to see the ice between them begin to thaw, though, as Kevin finds himself empathizing with his stepfather after certain events in his own life.

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"It'll be explained a little more, why there's that resentment there," Hartley promises. "As Kevin grows up, the relationships he has with people will evolve as well."

But are fans ready to bury the hatchet with Miguel? Understanding how he and Rebecca came to be an item may be the only way to find out.