Oliver's (Stephen Amell) refusal to tell Felicity (Emily Bett Rickards) about the kid he fathered with his former lover Samantha (Anna Hopkins) will come back to haunt him in The CW series "Arrow."

When the Green Arrow and The Flash (Grant Gustin) decided to take on immortal villain Vandal Savage (Casper Crump), the end result was nothing short of horrifying. Almost everyone died, and if not for Barry racing back in time to change what happened, there will be nothing left for the superheroes but regret. Vandal died instead and things almost went back to normal, but not for Oliver. In his brief jaunt in the past, he discovered something so shocking, he almost could not believe it was true.

It turned out that the child that he and Samantha made is alive and his name is William. His former fling lied to him about the child dying, when it fact, he's fine and growing fast. Barry also knew the truth, and he advised Oliver to tell Felicity about it before she learned his secret from someone else. Oliver, however, chose to stay quiet about it. He had no courage to tell his girlfriend the truth, as he feared it could ruin their relationship. His decision to keep the truth hidden would reportedly blow up in his face, as sooner rather than later, Felicity would get wind of his lies.

In an interview with Entertainment Weekly, executive producer Wendy Mericle said that the confrontation between Oliver and Felicity would be seen in the middle of the season. The revelation would reportedly have some serious consequences in their relationship, which would be amplified by the frequent appearance of Samantha.

"We're really excited about how that's going to change things and it's really going to raise the stakes and throw some wrenches into the works of their relationship, which so far this season it's been pretty smooth sailing. There will be some fallout for both of them," she shared.

Meanwhile, TV Line speculates that the mystery on who the person is in the grave in one of the promo stills for the series will be revealed in the fall finale. While Mericle did not give a definite timeline, she hinted that there might be more flash-forward scenes "here and there... right around midseason."

"We're definitely toying with that and when and if we do decide to do that, it will reveal even more pertinent information about not who's going to be in the grave but certainly where our characters are when that [death] happens," she added.

Arrow" season 4 fall finale airs Dec. 9 at 8 p.m. EST on The CW.