This Is Us‘ first Season 4 trailer doubled as a major casting announcement: The promo — which NBC released early Saturday (watch it here) — heralded the arrival of nearly a dozen new actors/actresses to the series.

In addition to the previously announced Jennifer Morrison, the list of This Is Us newbies also now includes Morrison’s former House co-star Omar Epps, as well as Psych‘s Timothy Omundson, Revenge‘s Nick Wechsler and filmmaker M. Night Shyamalan.

Now for the $1 million burning question: Who are they all playing? NBC isn’t saying, but the trailer offered enough clues for us to cobble together some theories. Click on the gallery above — or go here for direct access — to peruse our hunches, and then share your own best guesses in the comments. 

This Is Us returns with its fourth season on Tuesday, Sept. 24 (NBC, 9/8c).