I read that his paternal grandfather was Jewish on Wikipedia too, but the confirmation that he’s not exactly Jewish was from his current publicist Gina Hoffman after The Jewish Journal called Zac “a gorgeous Jewish boy”, so to me that’s pretty official.
I think he said he’s Jewish in the Workaholics video because it’s totally scripted, he had to say that so they could ask him to show his dick. In the Cinemax video, after Joel Stein calling Zac and Seth Jewish, he soon found Zac’s NOT Jewish in his bet with Ike Barinholtz on if Zac’s Jewish, and Joel said “I feel bad I called him a Jew earlier”.
Edit: Anyways I’m not expert on any aspects of Zac’s life, and I don’t really care about it too much, believe what you think it’s true:)
Could you pass the vibe to him?