With the recent revelation that classic X-Men storyline "Days of Future Past" would serve as the basis for the upcoming "X-Men: First Class" sequel (now titled, appropriately enough, "X-Men: Days of Future Past"), we couldn't help but wonder what actors from the original trilogy might pop up in cameo appearances. After all, the time-traveling nature of the "Future Past" concept certainly lends itself to the idea of older versions of Vaughn's crop of characters coming-face-to-face with their youthful counterparts.

So, will James McAvoy's Professor X come face-to-face with Patrick Stewart? Will Ian McKellen's older, more composed Magento advise Michael Fassbender? We haven't the slightest - but it sure is fun to dream.

Check out all ten of our cameo picks in the gallery below.

"X-Men: Days of Future Past" is slated for release on July 18, 2014.