Mad Men beauty January Jones has been making headlines with her interview — and eye-popping cleve — in the November issue of GQ. But a new report claims the marvelous bustline of TV’s Betty Draper may not be as authentic as it seems.

According to sources quoted in Friday’s edition of The New York Post’s PageSix Column, January’s boobies got a big boost thanks to the wonders of digital enhancement.

“They definitely did some significant retouching,” The Post snitch squeal. “It’s just par for the course these days with cover shoots.”

Not so says GQ, who claims January’s breasts can hold their own just fine without any help from Dr. Photoshop.

“Yes, they’re real. And they’re spectacular,” photo editor Dora Samo says: “People think that a person will look the same in every photograph, but that just doesn’t happen . . . Terry [Richardson] likes to work with harder lighting, and that can create a stronger shadow — that, and body position and perspective could give the illusion that her breasts are bigger. January Jones needed no help. Trust me.”