After nearly four years of dating, Johnson finally opened up about her relationship with Martin in an interview with Elle UK in December 2021. Briefly touching on their dynamic, the actress said, "We've been together for quite a while, and we go out sometimes, but we both work so much that it's nice to be at home and be cosy and private. Most of the partying takes place inside my house."
The same month, engagement rumours swirled as People published pictures of Johnson wearing a stunning Emerald gem on her ring finger, though the speculation was never confirmed.