Agents Of S.H.I.E.L.D.: FitzSimmons Takes It To The Next Level

It's been a long and complicated road, but sounds like the will-they-won't-they of Marvel's Agents of S.H.I.E.L.D.'s Leo Fitz and Jemma Simmons will finally reach the next level in next week's episodes, "Many Heads, One Tale."

"Their relationship will visibly change forever," executive producer Jed Whedon tells EW. "Their chemistry is something that was conceived, in creating the characters, as two people who are inseparable. We talked about many different versions of that before casting it — they're like brother and sister who are always bickering and they complete each other's sentences, drive each other crazy and are totally co-dependent."

Showrunner Jed Whedon added that the producers don't "want to string something out to the point of absurdity."

"When we first conceived the characters, we didn't think it would go this way," he said. "It was only in seeing them play it that their chemistry was so undeniable."

"For a while, that was the beautiful thing about the FitzSimmons love story is that, to everyone around them, it's so clearly obvious that they should be together, but to Fitz and Simmons, it seems like the most absurd idea ever to be anything beyond friends, working partners and each other's best friend," added showrunner Maurissa Tancharoen.

"We always have to keep it complicated," Whedon says. "And we continue to do a good job of that moving forward.

"This is the episode where they both will express their feelings finally about everything that's gone down."

Marvel's Agents of S.H.I.E.L.D. airs Tuesdays at 9 p.m. on ABC.