|Mademoiselle #1 (April 1969)
I included this image and the next so you could see how the head sheet information relates to the actual magazine issue it refers to. It seems "The Corby sisters" were somewhat well known to the public, and the novelty of two successful fashion model sisters was certainly appealing to this advertiser. This is not the only time the two appeared together in the same photo, but I don't believe it happened very often. The ad reads: "... demonstrated quite notably here by those clever girls - the Corby sisters, Colleen and Molly."
(Original scan by "ModelHistory".)