In an episode of the podcast "Office Ladies," which is hosted by former co-stars Jenna Fischer and Angela Kinsey — whose characters advised Michael not to get back together with Jan — the episode "The Job" is discussed at length. Fischer began the conversation by revealing that one fan actually asked her if Hardin got a breast augmentation just for the storyline (which would be quite the dedication to the role), to which Fischer confirmed that that wasn't the case. Instead, the costume and makeup departments had the task of working out a way to make it look like Jan had bigger breasts than Hardin actually does.
Fischer explained, "They designed this crazy bra for her that was filled with like a gazillion little cutlets and then they did this like makeup shadowing on her chest to create even more illusion of, like, swollen cleavage and all of that" (via CheatSheet). Then, Hardin had to wear the specialized bra for every episode she was in thereafter, to keep up the continuity — which, in and of itself, is also quite dedicated.
