Fox, 34, posed next to Kelly, 30, in a bikini top with a towel wrapped around her waist. The rapper was shirtless and also had a towel wrapped around his waist.
“Achingly Beautiful Boy... My heart is yours,” she captioned the photo on Wednesday.
The post marks the first photo the “Jennifer’s Body” star has posted of Kelly as a couple.
She previously shared a picture of the pair as promotion for the rapper’s music video for his song “Bloody Valentine,” which she starred in.
Kelly posted his first couple photo on Fox last week. “Waited for eternity to find you again …” he captioned the picture with his girlfriend.
Fox recently opened up about her relationship with Kelly in a joint interview for Lala Kent and Randall Emmett’s podcast, “Give Them Lala… with Randall.”
“I knew right away that he was what I call a twin flame,” the mom of three said of meeting the rapper on the set of their upcoming movie. “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.”
Fox 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.
Kelly also shares a daughter, Cassie, 12, with his ex-girlfriend Emma Cannon.