In the Marvel Cinematic Universe, the Infinity Stones have been revealed one-by-one.
So far, four of the six stones have been revealed, leaving only the Time Stone and the Soul Stone left unseen, according to Screen Rant.
The next film in the MCU to be released is "Doctor Strange," which many fans believe will feature the reveal of one more Infinity Stone.
Fans have theorized that Doctor Strange's Eye of Agamotto is in fact one of the Infinity Stones, specifically the Time Stone. In an interview with Entertainment Weekly, head of Marvel Studios Kevin Feige and director Scott Derrickson, hinted this theory may be true.
Feige said the Eye of Agamotto gives Doctor Strange the ability to "screw around with time," adding that designing the amulet "wasn't that difficult."
"It was so cool," Derrickson told Entertainment Weekly. "We knew we didn't have to improve greatly upon what was in the comics for it to be interesting for a modern audience."
Fans believe the use of an Infinity Stone in the Eye of Agamotto would make sense in the context of the MCU, connecting it to the other films and ensuring that Doctor Strange is involved in the upcoming "Infinity War," in which the Avengers will face off against villain Thanos.
"Doctor Strange" is set to premiere Nov. 4.