It sounds like Avengers: Infinity War's impressive scope will include a blast from the past.

A new casting call for 'Mary Lou' - Infinity War's working title - suggests that the film will include some sort of 1960s flashback. The announcement, which is courtesy of Central Casting Georgia, asks for actresses to play secretaries and female engineers in the 1960s.

"Secretaries: Looking for women who appear to be Caucasian, 20s-50s, to portray 1960s secretaries/clerks. Hair must be period-appropriate: no longer than shoulder length, no dye, no modern colors or cuts. Must be dress size 0-8."

"Female Engineers: Looking for women who appear to be Caucasian, 20s-50s, to portray 1960s engineers in this VERY small scene. Hair must be period-appropriate: short hair, no longer than shoulder length, no dye, no modern colors or cuts. Must be dress size 0-8."

No other details are known about the scene, other than that the scene involving the secretaries will film on October 10th and 11th, while the female engineers scene is set to film on October 12th, 13th, and 16th.

Casting calls like these have caused quite a bit of speculation amongst fans during Infinity War's filming. Everything from Nick Fury's potential return to an appearance by Captain Marvel have been decoded by these announcements. While this statement is much more vague, there's a chance that it could reveal something surprising about the next two Avengers installments.