During an appearance in Beijing this week, the 50-year-old was asked whether he was, in fact, going to tie the knot.
"The fact that I'm wearing a chick's ring on my finger is probably a dead giveaway. Not very subtle," Johnny replied, indicating a single diamond on a band on his wedding finger.
His comments follow months of unconfirmed reports of his engagement to 27-year-old Amber, who starred alongside him in the 2011 film Rum Diary.
While promoting his new film Transcendence in China on Monday, Johnny also fielded a question about any potential wedding plans.
"I think that I would be better at making women's shoes than I would be at wedding planning, I can't plan anything," he admitted. "I'm really bad at that stuff."
It will be the first marriage for Amber, and the second for Johnny, who was married to Lori Anne Allison for two years in the mid-80s.
He was in a relationship with Vanessa Paradis, the mother of his two children Lily-Rose, 14, and Jack, 11, for 14 years before they announced their split in June 2012.
In his new film, Johnny plays a terminally ill scientist who downloads his mind into a computer. Transcendence also stars Rebecca Hall as his wife, and Morgan Freeman.
"The technology that exists within the film, what I find most fascinating is that a lot of it exists already, and by all accounts from scholars and professors and scientists that species of technology is not far away, that kind of artificial intelligence," Johnny said in an interview.
"It's one of those films that one person is forced to make a choice in an instant, when your loved one is dying and you have a split-second decision if you have the ability to upload their consciousness into a computer, would you do that?
"It's quite a strange decision to make, but for love I think we would all do it."