Shane Gillis had some familiar faces in the crowd for "Saturday Night Live" this weekend ... as San Francisco 49ers stars Christian McCaffrey, George Kittle and Kyle Juszczyk were present for his hosting gig.
Kittle posted the trio's NYC adventure to his Instagram page on Sunday night ... sharing some behind-the-scenes flicks from Studio 8H -- including a selfie with Mike Myers, who played Elon Musk in the episode.