New "Castle" showrunners Terence Paul Winter and Alexi Hawley have gone out of their way to assure fans that new security expert Hayley Vargas (Toks Olagundoye) will not come to be a problem for Rick (Nathan Fillion) and Kate's (Stana Katic) relationship.

But that doesn't mean that she won't find herself at the center of a full-blown love triangle of some sort as the new season plays out.

"She is pretty cute, and I think Esposito has noticed that for sure," Jon Huertas told TV Guide of his character. "He's admiring the scenery right now."

In time, the "quick-witted and free-spirited" security expert could be the one to put the final nail in Esposito and Lanie's (Tamala Jones) on-again, off-again relationship.

"Lanie hasn't necessarily noticed, but a triangle is a huge possibility and something I think we're definitely going to see this season," said Huertas.

Winter also commented on Esposito and Hayley's potential coupling, saying, "There is an obvious flirtation between the two that's come up in a couple episodes."

Hayley is also slated to spend her early days as a member of the crew serving as a mentor to Rick's daughter Alexis (Molly C. Quinn), helping her "find herself," as Alexis seeks to settle into adulthood and her profession.

"What we've shot with [Alexis and Hayley] together is magic, it really is" Winter told TV Line.

While acknowledging that, as Castle's wife, Kate has largely played the role of mentor in seasons past, Hawley told Entertainment Weekly that show executives are particularly looking forward to having Hayley now serve in that capacity because she can adopt the role of a big sister in offering advice.

The new season premiere, titled "XY," airs on ABC Monday, Sept. 21.