The 27-year-old actress sparked speculation she is set to marry the handsome star as she stepped out in LA this week.
According to E! News, Amber dined with a female friend at Ago restaurant, and as she left did everything she could to shield her left hand from photographers. She even waited for the valet driver to open the car door so she didn't have to show her finger.
But for a brief moment, the ring appeared.
Johnny met Amber on the set of The Rum Diaries in 2011
Johnny, 50, and Amber, who were first linked at the beginning of 2012, stepped out together as recently as Saturday, when they took their very private romance public at a star-studded gala.
Amber was previously in a four-year relationship with ex-girlfriend Tasya van Ree, while Johnny had a relationship with Vanessa Paradis, the mother of his two children, for 14 years.