When Mendes walked the red carpet with boyfriend and Riverdale co-star Charles Melton to celebrate the world premiere of The Sun Is Also A Star earlier this week, fans caught a glimpse of the tiny side-boob tattoo peeking out from beneath the actress' yellow gown. It's not clear when, exactly, Mendes got the ink, but she told Latina in a 2017 interview that the tattoo — which says "to build a home” — is sentimental to her because building a home within herself has always been a major goal. After spending most of her childhood moving around, Mendes learned that finding stability within herself was the only aspect of her life she could fully control.