The actress from Transformers tagged the musician in a photograph depicting her kneeling, covered in a dark substance, while gently holding her baby bump.
Fox, who disclosed last year that she had suffered a miscarriage during a previous pregnancy, also shared an image of a positive pregnancy test alongside the portrait.
The actress, who has been in a relationship with Kelly since 2020, captioned the images: “Nothing is ever really lost. welcome back.”
Fox has previously discussed her miscarriage on ABC’s Good Morning America, stating, “I’ve never been through anything like that before in my life. It was very difficult for both of us.”
She added, “It sent us on a very wild journey together and separately – trying to navigate what does this mean and why did this happen?”
Additionally, she expressed her experiences in her book, Pretty Boys are Poisonous, through two poems.
In an interview with Women’s Wear Daily, Fox also revealed that she had experienced an ectopic pregnancy on another occasion, which occurs when a fertilized egg implants outside the womb, typically in one of the fallopian tubes.
The American actress is a mother of three, while Machine Gun Kelly has a daughter from a previous relationship.