The 30-year-old artist -- real name Colson Baker -- took to Instagram to share a black-and-white mirror selfie of the two standing next to each other while making silly faces.
"Waited for eternity to find you again," Kelly captioned the snapshot on Tuesday, which features Fox, 34, rocking a black sports bra and matching pants, while Kelly wore a graphic tee.
The pair met earlier this year while filming the upcoming movie “Midnight in the Switchgrass.”
The actress revealed that when she found out Kelly would be her co-star, she instantly felt “something was going to come from that."
"I was like, 'Who is going to play this role?' And he was like, 'Oh, we just got Machine Gun Kelly,' and immediately, I was like, 'Uh oh,'" the “Transformers” actress said.
Emmett, who directed the film, responded: "Really?"
"Yeah, because I knew. I could feel that some wild s--t was going to happen to me from that meeting, but I wasn't yet sure what,” Fox continued. “I just felt it like, deep in my soul that something was going to come from that.”
Although Fox felt a strong connection to Kelly before they met, the “Bad Things” rapper wasn’t sure how their connection would be.
He admitted to waiting outside of his trailer every day “to catch one glimpse of eye contact” with Fox.
"She would have to get out of her car. There were, like, five steps between the car and the trailer. And I would just sit there and hope," Kelly revealed.
Fox added: “I knew right away that he was what I call a twin flame. Instead of a soul mate, a twin flame is actually where a soul has ascended into a high enough level that it can be split into two different bodies at the same time. So we're actually two halves of the same soul, I think. And I said that to him almost immediately, because I felt it right away.”
The mom of three then shared that she invited Kelly into her trailer for lunch on the second day of filming to learn more about his astrology. “I went deep right away. I knew before I even did his chart, I said to him, he has a Pisces moon. I could tell by his energy,” she said.
Green, 47, and Fox were married for almost 10 years and share kids, Noah, 7, Bodhi, 6, and Journey, 3, together.
Fox News' Naledi Ushe contributed to this report