Claims that all seasons of "American Horror Story" are intertwined with one another are no longer a theory.

Series' co-creator Ryan Murphy confirmed the speculations that all installments of the hit FX anthology series are connected when he was recently asked by Entertainment Weekly about Lily Rabe's return to the show.

"I don't want to say much about [Rabe's comeback] but obviously she's playing Sister Mary Eunice," Murphy said. "The interesting thing about doing a show like this is every season is incredibly its own story and its own beginning, middle and end. Its own journey. But we have always from the very beginning in the intertwining mythologies and how things connect."

He continued: "This is the first year where we begin to tell you that season two ("Asylum") is connected to season four ("Freak Show") which is connected to season one ("Murder House"). People have started to write articles about that. A lot of their hypotheses have been completely right on. That's the fun of the show."

"Hopefully by the end of the run, be it 10 years or 15 years, people will be able to stand back and be able to say, 'Oh that was connected to x,' the 48-year-old Primetime Emmy winner added.

As of the moment, Pepper's (Naomi Grossman) storyline is the only clear confirmation that there is indeed connectedness among the series' installments, but Murphy assured fans that there are more pieces of evidence coming out that would support the idea.

"We're just beginning to tell you how they're connected," Murphy told EW. "They're all very separate but there are clues every season that we're now telling you how the different worlds are intertwined."

As Murphy pointed out, the return of Sister Mary Eunice from "Asylum" has something to do with how the microcephalic character Pepper - also first seen in "Asylum" - will end up to Briarcliff Manor, the central location and focus of the series' second installment.

In "Asylum," Pepper was committed to Briarcliff Manor after she was convicted of drowning her sister's son and cutting off his ears. However, the character claimed in Episode 10 of the said season that she was falsely accused of murdering and mutilating her nephew.

During a recent group interview to promote the DVD and Blu-ray releases of "Coven," Grossman teased that Pepper's sister may also be introduced in "Freak Show," according to Popsugar.

Meanwhile, Grossman is very much grateful for the opportunity to play Pepper once again. "Pepper is a gift that keeps on giving," Grossman said in a recent interview while filming the series in New Orleans, according to Albuquerque Journal. "At the end of last season [Asylum], it was all downhill from there. Then I got pulled back for the show and it's just been amazing."

"American Horror Story: Freak Show" airs every Wednesdays 10:00 p.m. on FX.