Megan Fox and Machine Gun Kelly went on a "wild journey" when she suffered a miscarriage.
The 37-year-old actress - who has sons Noah, 11, Bodhi, nine, and Journey, seven, with ex-husband Brian Austin Green - revealed in her new poetry book, 'Pretty Boys Are Poisonous', that she lost a baby girl when she was 10 weeks pregnant, and she's now reflected on how both she and her fiancé found it "very difficult" to cope with the loss.
Speaking on 'Good Morning America', she said: "I had never been through anything like that before in my life.
"I have three kids, so it was very difficult for both of us. And it sent us on a very wild journey together and separately, and together and apart, and together and apart, and together and apart, trying to navigate, 'What does this mean? Why did this happen?'"
In her book, Fox also wrote about being a victim of abuse and the 'Transformers' star explained she has secretly been in numerous toxic relationships with "horrific" people.
She said: "It's not an expose that I wrote or a memoir.
"But throughout my life, I have been in at least one physically abusive relationship and several psychologically very abusive relationships.
"I have only been publicly connected to a few people, but I shared energy, I guess you could say, [with] people who were horrific people.
"Also very famous. Very famous people. But no one knows that I was involved with those people."
Fox credited MKG, whose real name is Colson Baker, for encouraging her to write her book because she needed to find an outlet for her feelings before they made her "sick".
She said: "The person who actually told me I should write a poetry book is Colson.
"It was something inside of me that had to come out or else it was going to make me sick.
"Some of it is definitely a metaphor. None of it is what I would say fictional. Those are all real life experiences that I had."
In Fox’s book, the 'Jennifer's Body' actress included a drawing of a woman holding a baby and made reference to her miscarriage.
She wrote: "There is an ultrasound by your side of the bed, 10 weeks and 1 day … do you think that if she could have, she would have left a suicide note?"
MGK has a 14-year-old daughter, Casie, from a previous relationship.